Dealing with bad news

today I was given the news that I need to move out of the shed n my home ill update you with more info when I have it hopefully I will find somewhere soon

useful item magnetic parts tray

hi folks today I thought Id share another useful item I found on ebay a magnetic parts tray which is very useful for keeping screws and nuts in when u are taking things apart here is the link if you'd like to check it out

losing days

today was the first day in a while I had the whole day off and could get in the shed but the power was taken out by a tree across the power lines and it was out for about 14 hours meaning I couldn't get any work done out there today and because of this I have decided to invest in a generator as the winter is coming and I know there will be many more times that I will be without power

dobby

pokemon go mewtwo raid

so today I went to do an ex pokemon go raid and I caught mewtwo I know this isn't my normal content but I enjoyed it  so  I hope you will 

Electrical Contact Cleaner

hi guys I just wanted to share this Electrical Contact Cleaner I got from ebay to it works really well and does the job

long days

today has been another long day and I have not got much done I did get  into the shed today which was nice hopefully things will get easier soon

dobby

Electronic noise

In electronics, noise is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly as it is produced by several different effects. Thermal noise is unavoidable at non-zero temperature (see fluctuation-dissipation theorem), while other types depend mostly on device type (such as shot noise, which needs a steep potential barrier) or manufacturing quality and semiconductor defects, such as conductance fluctuations, including 1/f noise.
In communication systems, noise is an error or undesired random disturbance of a useful information signal. The noise is a summation of unwanted or disturbing energy from natural and sometimes man-made sources. Noise is, however, typically distinguished from interference, for example in the signal-to-noise ratio (SNR), signal-to-interference ratio (SIR) and signal-to-noise plus interference ratio (SNIR) measures. Noise is also typically distinguished from distortion, which is an unwanted systematic alteration of the signal waveform by the communication equipment, for example in the signal-to-noise and distortion ratio (SINAD) and total harmonic distortion plus noise (THD+N).
While noise is generally unwanted, it can serve a useful purpose in some applications, such as random number generation or dither.

Jump wire

A jump wire (also known as jumper, jumper wire, jumper cable, DuPont wire, or DuPont cable – named for one manufacturer of them) is an electrical wire or group of them in a cable with a connector or pin at each end (or sometimes without them – simply "tinned"), which is normally used to interconnect the components of a breadboard or other prototype or test circuit, internally or with other equipment or components, without soldering.
Individual jump wires are fitted by inserting their "end connectors" into the slots provided in a breadboard, the header connector of a circuit board, or a piece of test equipment.

There are different types of jumper wires. Some have the same type of electrical connector at both ends, while others have different connectors. Some common connectors are:

• Solid tips – are used to connect on/with a breadboard or female header connector. The arrangement of the elements and ease of insertion on a breadboard allows increasing the mounting density of both components and jump wires without fear of short-circuits. The jump wires vary in size and colour to distinguish the different working signals.
• Crocodile clips – are used, among other applications, to temporarily bridge sensors, buttons and other elements of prototypes with components or equipment that have arbitrary connectors, wires, screw terminals, etc.
• Banana connectors – are commonly used on test equipment for DC and low-frequency AC signals.
• Registered jack (RJnn) – are commonly used in telephone (RJ11) and computer networking (RJ45).
• RCA connectors – are often used for audio, low-resolution composite video signals, or other low-frequency applications requiring a shielded cable.
• RF connectors – are used to carry radio frequency signals between circuits, test equipment, and antennas.

Inductive charging

Inductive charging (also known as wireless charging or cordless charging) uses an electromagnetic field to transfer energy between two objects through electromagnetic induction. This is usually done with a charging station. Energy is sent through an inductive coupling to an electrical device, which can then use that energy to charge batteries or run the device.
Induction chargers use an induction coil to create an alternating electromagnetic field from within a charging base, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electric current to charge the battery. The two induction coils in proximity combine to form an electrical transformer. Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling.
Recent improvements to this resonant system include using a movable transmission coil (i.e. mounted on an elevating platform or arm) and the use of other materials for the receiver coil made of silver plated copper or sometimes aluminium to minimize weight and decrease resistance due to the skin effect.

Advantages

Protected connections – No corrosion when the electronics are all enclosed, away from water or oxygen in the atmosphere. Less risk of electrical faults such as short circuit due to insulation failure, especially where connections are made or broken frequently.
Low infection risk – For embedded medical devices, transmission of power via a magnetic field passing through the skin avoids the infection risks associated with wires penetrating the skin.
Durability – Without the need to constantly plug and unplug the device, there is significantly less wear and tear on the socket of the device and the attaching cable.
Increased convenience and aesthetic quality – No need for cables.
Automated high power inductive charging of electric vehicles allows for more frequent charging events and consequential driving range extension.
Inductive charging systems can be operated automatically without dependence on people to plug and unplug. This results in higher reliability.
Autonomous driving technology, when applied to electric vehicles, depends on autonomous electric charging—automatic operation of inductive charging solves this problem.
Inductive charging of electric vehicles at high power levels enables charging of electric vehicles while in motion (also known as dynamic charging).

Disadvantages

The following disadvantages have been noted for low power (i.e., less than 100 watts) inductive charging devices. These disadvantages may not be applicable to high power (i.e. greater than 5 kilowatts) electric vehicle inductive charging systems.

• Slower charging – Due to the lower efficiency, devices take longer to charge when supplied power is the same amount.
• More expensive – Inductive charging also requires drive electronics and coils in both device and charger, increasing the complexity and cost of manufacturing.
• Inconvenience - When a mobile device is connected to a cable, it can be moved around (albeit in a limited range) and operated while charging. In most implementations of inductive charging, the mobile device must be left on a pad to charge, and thus can't be moved around or easily operated while charging.

Newer approaches reduce transfer losses through the use of ultra thin coils, higher frequencies, and optimized drive electronics. This results in more efficient and compact chargers and receivers, facilitating their integration into mobile devices or batteries with minimal changes required.These technologies provide charging times comparable to wired approaches, and they are rapidly finding their way into mobile devices.
For example, the Magne Charge vehicle recharger system employs high-frequency induction to deliver high power at an efficiency of 86% (6.6 kW power delivery from a 7.68 kW power draw).
Standards

• Magne Charge, a largely obsolete inductive charging system, also known as J1773, used to charge battery electric vehicles (BEV) formerly made by General Motors.
• Qi, an interface standard developed by the Wireless Power Consortium for inductive electrical power transfer. At the time of July 2017, it is the most famous standard in the world, more than 200 million devices supporting this interface.

AirFuel Alliance:

In January 2012, the IEEE announced the initiation of the Power Matters Alliance (PMA) under the IEEE Standards Association (IEEE-SA) Industry Connections. The alliance is formed to publish set of standards for inductive power that are safe and energy efficient, and have smart power management. The PMA will also focus on the creation of an inductive power ecosystem
Rezence was an interface standard developed by the Alliance for Wireless Power (A4WP).
A4WP and PMA merged into the AirFuel Alliance in 2015.

keeping going

sometimes you need to keep going other times you need to know when to stop I found this out week when I was to ill to keep going there is a limit on how much a human can take when you stop its always best to take stock of what has happen and change the bad things for better things my plans our to keep this blog going and to make it better with more electronics  and other tech stuff so please bear with me .

Being ill

I hate feeling ill for the most I try to solder on and not miss a day of work although today I felt so bad I had to miss a day of work and just lay in bed which was kinda what I needed I read a book and mainly slept which was nice hopefully I feel better soon and can start working tomorrow

power bank review coming soon

hi just wanted to let you know that I will reviewing a power bank very shortly here is a link to check out the power bank  I will be reviewing

late and quick update

after a long day at work I only have time for this quick update just to let you know I am planning to change my job to one that will give me more free time stay tuned for more info in the coming day

dobby

struggling with work

hi folks I'm still struggling with my work load I had hoped it would slow down but I seems to of really ramped up again I trying keep up with the posts but I may have to miss a day or two soon and for that I am sorry

dobby

Digital signal processor

A digital signal processor (DSP) is a specialized microprocessor (or a SIP block), with its architecture optimized for the operational needs of digital signal processing.
The goal of DSPs is usually to measure, filter or compress continuous real-world analog signals. Most general-purpose microprocessors can also execute digital signal processing algorithms successfully, but dedicated DSPs usually have better power efficiency thus they are more suitable in portable devices such as mobile phones because of power consumption constraints. DSPs often use special memory architectures that are able to fetch multiple data or instructions at the same time.

Overview

Digital signal processing algorithms typically require a large number of mathematical operations to be performed quickly and repeatedly on a series of data samples. Signals (perhaps from audio or video sensors) are constantly converted from analog to digital, manipulated digitally, and then converted back to analog form. Many DSP applications have constraints on latency; that is, for the system to work, the DSP operation must be completed within some fixed time, and deferred (or batch) processing is not viable.
Most general-purpose microprocessors and operating systems can execute DSP algorithms successfully, but are not suitable for use in portable devices such as mobile phones and PDAs because of power efficiency constraints.A specialized digital signal processor, however, will tend to provide a lower-cost solution, with better performance, lower latency, and no requirements for specialised cooling or large batteries.
Such performance improvements have led to the introduction of digital signal processing in commercial communications satellites where hundreds or even thousands of analogue filters, switches, frequency converters and so on are required to receive and process the uplinked signals and ready them for downlinking, and can be replaced with specialised DSPs with a significant benefits to the satellites weight, power consumption, complexity/cost of construction, reliability and flexibility of operation. For example, the SES-12 and SES-14 satellites from operator SES, both intended for launch in 2017, are being built by Airbus Defence and Space with 25% of capacity using DSP.
The architecture of a digital signal processor is optimized specifically for digital signal processing. Most also support some of the features as an applications processor or microcontroller, since signal processing is rarely the only task of a system. Some useful features for optimizing DSP algorithms are outlined below.

Architecture

Software architecture

By the standards of general-purpose processors, DSP instruction sets are often highly irregular; while traditional instruction sets are made up of more general instructions that allow them to perform a wider variety of operations, instruction sets optimized for digital signal processing contain instructions for common mathematical operations that occur frequently in DSP calculations. Both traditional and DSP-optimized instruction sets are able to compute any arbitrary operation but an operation that might require multiple ARM or x86 instructions to compute might require only one instruction in a DSP optimized instruction set.
One implication for software architecture is that hand-optimized assembly-code routines are commonly packaged into libraries for re-use, instead of relying on advanced compiler technologies to handle essential algorithms.^{[clarification} Even with modern compiler optimizations hand-optimized assembly code is more efficient and many common algorithms involved in DSP calculations are hand-written in order to take full advantage of the architectural optimizations.

Instruction sets

• multiply–accumulates (MACs, including fused multiply–add, FMA) operations
  • used extensively in all kinds of matrix operations
    • convolution for filtering
    • dot product
    • polynomial evaluation
  • Fundamental DSP algorithms depend heavily on multiply–accumulate performance
    • FIR filters
    • Fast Fourier transform (FFT)
• Instructions to increase parallelism:
  • SIMD
  • VLIW
  • superscalar architecture
• Specialized instructions for modulo addressing in ring buffers and bit-reversed addressing mode for FFT cross-referencing
• Digital signal processors sometimes use time-stationary encoding to simplify hardware and increase coding efficiency.
• Multiple arithmetic units may require memory architectures to support several accesses per instruction cycle
• Special loop controls, such as architectural support for executing a few instruction words in a very tight loop without overhead for instruction fetches or exit testing

Data instructions

• Saturation arithmetic, in which operations that produce overflows will accumulate at the maximum (or minimum) values that the register can hold rather than wrapping around (maximum+1 doesn't overflow to minimum as in many general-purpose CPUs, instead it stays at maximum). Sometimes various sticky bits operation modes are available.
• Fixed-point arithmetic is often used to speed up arithmetic processing
• Single-cycle operations to increase the benefits of pipelining

Program flow

• Floating-point unit integrated directly into the datapath
• Pipelined architecture
• Highly parallel multiplier–accumulators (MAC units)
• Hardware-controlled looping, to reduce or eliminate the overhead required for looping operations

Hardware architecture

In engineering, hardware architecture refers to the identification of a system's physical components and their interrelationships. This description, often called a hardware design model, allows hardware designers to understand how their components fit into a system architecture and provides to software component designers important information needed for software development and integration. Clear definition of a hardware architecture allows the various traditional engineering disciplines (e.g., electrical and mechanical engineering) to work more effectively together to develop and manufacture new machines, devices and components.
Hardware is also an expression used within the computer engineering industry to explicitly distinguish the (electronic computer) hardware from the software that runs on it. But hardware, within the automation and software engineering disciplines, need not simply be a computer of some sort. A modern automobile runs vastly more software than the Apollo spacecraft. Also, modern aircraft cannot function without running tens of millions of computer instructions embedded and distributed throughout the aircraft and resident in both standard computer hardware and in specialized hardware components such as IC wired logic gates, analog and hybrid devices, and other digital components. The need to effectively model how separate physical components combine to form complex systems is important over a wide range of applications, including computers, personal digital assistants (PDAs), cell phones, surgical instrumentation, satellites, and submarines.

Memory architecture

DSPs are usually optimized for streaming data and use special memory architectures that are able to fetch multiple data or instructions at the same time, such as the Harvard architecture or Modified von Neumann architecture, which use separate program and data memories (sometimes even concurrent access on multiple data buses).
DSPs can sometimes rely on supporting code to know about cache hierarchies and the associated delays. This is a tradeoff that allows for better performance. In addition, extensive use of DMA is employed.

Isopropyl alcohol

Isopropyl alcohol (IUPAC name propan-2-ol), also called dimethyl carbinol or, incorrectly,isopropanol, is a compound with the chemical formula C₃H₈O or C₃H₇OH or CH₃CHOHCH₃ (sometimes represented as i-PrOH). It is a colorless, flammable chemical compound with a strong odor. As an isopropyl group linked to a hydroxyl group, it is the simplest example of a secondary alcohol, where the alcohol carbon atom is attached to two other carbon atoms, sometimes shown as (CH₃)₂CHOH. It is a structural isomer of 1-propanol. It has a wide variety of industrial and household uses, and is a common ingredient in chemicals such as antiseptics, disinfectants and detergents.

Uses

In 1990, 45 thousand metric tons of isopropyl alcohol were used in the United States. The vast majority of isopropyl alcohol was used as a solvent for coatings or for industrial processes. In that year, 5.4 thousand metric tons were consumed for household use and in personal care products. Isopropyl alcohol in particular is popular for pharmaceutical applications, it is presumed due to the low toxicity of any residues. Some isopropyl alcohol is used as a chemical intermediate. Isopropyl alcohol may be converted to acetone, but the cumene process is more significant. It is also used as a gasoline additive.

Solvent

Isopropyl alcohol dissolves a wide range of non-polar compounds. It also evaporates quickly, leaves nearly zero oil traces, compared to ethanol, and is relatively non-toxic, compared to alternative solvents. Thus, it is used widely as a solvent and as a cleaning fluid, especially for dissolving oils. Together with ethanol, n-butanol, and methanol, it belongs to the group of alcohol solvents, about 6.4 million tonnes of which were utilized worldwide in 2011.
Examples of this application include cleaning electronic devices such as contact pins (like those on ROM cartridges), magnetic tape and disk heads (such as those in audio and video tape recorders and floppy disk drives), the lenses of lasers in optical disc drives (e.g., CD, DVD) and removing thermal paste from heatsinks and IC packages (such as CPUs).

Thermal grease

Thermal grease (also called CPU grease, heat paste, heat sink compound, heat sink paste, thermal compound, thermal gel, thermal interface material, or thermal paste) is a kind of thermally conductive (but usually electrically insulating) compound, which is commonly used as an interface between heat sinks and heat sources (e.g., high-power semiconductor devices). The main role of thermal grease is to eliminate air gaps or spaces (which act as thermal insulator) from the interface area so as to maximize heat transfer. Thermal grease is an example of a thermal interface material.
As opposed to thermal adhesive, thermal grease does not add mechanical strength to the bond between heat source and heat sink. It will have to be coupled with a mechanical fixation mechanism such as screws, allowing for pressure between the two, spreading the thermal grease onto the heat source.

Composition

Thermal grease consists of a polymerizable liquid matrix and large volume fractions of electrically insulating, but thermally conductive filler. Typical matrix materials are epoxies, silicones, urethanes, and acrylates, solvent-based systems, hot-melt adhesives, and pressure-sensitive adhesive tapes are also available. Aluminum oxide, boron nitride, zinc oxide, and increasingly aluminum nitride are used as fillers for these types of adhesives. The filler loading can be as high as 70–80 wt %, and the fillers raise the thermal conductivity of the base matrix from 0.17–0.3 watts per meter Kelvin or W/(m·K), up to about 2 W/(m·K).
Silver thermal compounds may have a conductivity of 3 to 8 W/(m·K) or more. However, metal-based thermal grease can be electrically conductive and capacitive; if some flows onto the circuits it can cause malfunctioning and damage

TRIAC

TRIAC, from triode for alternating current, is a generic trademark for a three terminal electronic component that conducts current in either direction when triggered. Its formal name is bidirectional triode thyristor or bilateral triode thyristor. A thyristor is analogous to a relay in that a small voltage and current can control a much larger voltage and current. The illustration on the right shows the circuit symbol for a TRIAC where A1 is Anode 1, A2 is Anode 2, and G is Gate. Anode 1 and Anode 2 are normally termed Main Terminal 1 (MT1) and Main Terminal 2 (MT2) respectively.
TRIACs are a subset of thyristors and are related to silicon controlled rectifiers (SCRs). TRIACs differ from SCRs in that they allow current flow in both directions, whereas an SCR can only conduct current in a single direction. Most TRIACs can be triggered by applying either a positive or negative voltage to the gate (an SCR requires a positive voltage). Once triggered, SCRs and TRIACs continue to conduct, even if the gate current ceases, until the main current drops below a certain level called the holding current.
Gate turn-off thyristors (GTOs) are similar to TRIACs but provide more control by turning off when the gate signal ceases.
TRIACs' bidirectionality makes them convenient switches for alternating-current (AC). In addition, applying a trigger at a controlled phase angle of the AC in the main circuit allows control of the average current flowing into a load (phase control). This is commonly used for controlling the speed of induction motors, dimming lamps, and controlling electric heaters.

Kapton

Kapton is a polyimide film developed by DuPont in the late 1960sthat remains stable across a wide range of temperatures, from −269 to +400 °C (−452 to 752 °F; 4–673 K).Kapton is used in, among other things, flexible printed circuits (flexible electronics) and thermal blankets used on spacecraft, satellites, and various space instruments.
The chemical name for Kapton K and HN is poly (4,4'-oxydiphenylene-pyromellitimide). It is produced from the condensation of pyromellitic dianhydride and 4,4'-oxydiphenylamine. Kapton synthesis is an example of the use of a dianhydride in step polymerization. The intermediate polymer, known as a "poly(amic acid)", is soluble because of strong hydrogen bonds to the polar solvents usually employed in the reaction. The ring closure is carried out at high temperatures (200–300 °C, 473–573 K

Electronics manufacturing

Due to its large range of temperature stability, and its electrical isolation ability, Kapton tape is usually used in electronic manufacturing as an insulation and protection layer on electrostatic sensitive and fragile components. As it can sustain the temperature needed for a reflow soldering operation, its protection is available throughout the whole production process, and Kapton is often still present in the final consumer product.

3D printing

Kapton and ABS adhere to each other very well, which has led to widespread use of Kapton as a build surface for 3D printers. Kapton is laid down on a flat surface and the ABS is extruded on to the Kapton surface. The ABS part being printed will not detach from the build platform as it cools and shrinks, a common cause of print failure by warping of the part.

NodeMCU

NodeMCU is an open source IoT platform.^[ It includes firmware which runs on the ESP8266 Wi-Fi SoC from Espressif Systems, and hardware which is based on the ESP-12 module. The term "NodeMCU" by default refers to the firmware rather than the dev kits. The firmware uses the Lua scripting language. It is based on the eLua project, and built on the Espressif Non-OS SDK for ESP8266. It uses many open source projects, such as lua-cjson, and spiffs.

History

NodeMCU was created shortly after the ESP8266 came out. On December 30, 2013, Espressif Systemsbegan production of the ESP8266. The ESP8266 is a Wi-Fi SoC integrated with a Tensilica Xtensa LX106 core, widely used in IoT applications (see related projects). NodeMCU started on 13 Oct 2014, when Hong committed the first file of nodemcu-firmware to GitHub. Two months later, the project expanded to include an open-hardware platform when developer Huang R committed the gerber file of an ESP8266 board, named devkit v0.9. Later that month, Tuan PM ported MQTT client library from Contiki to the ESP8266 SoC platform, and committed to NodeMCU project, then NodeMCU was able to support the MQTT IoT protocol, using Lua to access the MQTT broker. Another important update was made on 30 Jan 2015, when Devsaurus ported the u8glib to NodeMCU project, enabling NodeMCU to easily drive LCD, Screen, OLED, even VGA displays.
In summer 2015 the creators abandoned the firmware project and a group of independent but dedicated contributors took over. By summer 2016 the NodeMCU included more than 40 different modules. Due to resource constraints users need to select the modules relevant for their project and build a firmware tailored to their needs.

Related projects

ESP8266 Arduino Core

As Arduino.cc began developing new MCU boards based on non-AVR processors like the ARM/SAM MCU and used in the Arduino Due, they needed to modify the Arduino IDE so that it would be relatively easy to change the IDE to support alternate tool chains to allow Arduino C/C++ to be compiled down to these new processors. They did this with the introduction of the Board Manager and the SAM Core. A "core" is the collection of software components required by the Board Manager and the Arduino IDE to compile an Arduino C/C++ source file down to the target MCU's machine language. Some creative ESP8266 enthusiasts have developed an Arduino core for the ESP8266 WiFi SoC that is available at the GitHub ESP8266 Core webpage. This is what is popularly called the "ESP8266 Core for the Arduino IDE" and it has become one of the leading software development platforms for the various ESP8266 based modules and development boards, including NodeMCUs. For more information on all things ESP8266, check out the ESP8266 Community Forum on GitHub.

The Button

The Button is a Wi-Fi connected push button designed by Peter R Jennings. The Button is designed for single-purpose, internet-enabled functions. When the button is pressed, a connection is made to a web server which will perform the desired task. Applications include a doorbell or panic button.

NodeUSB

NodeUSB is an open IoT platform about the size of a standard USB stick. It was designed to leverage NodeMCU (Lua) for easy programming and has the extra feature of USB capability. It is ideal for Plug-n-Play solutions, allowing easy prototyping for developers.

ijWatch

ijWatch is an open-hardware and open-source Wi-Fi smartwatch, using an OLED screen and running NodeMCU firmware. The author believes it may be the first smartwatch. (As in, the watch itself is fully functional without the pairing of another bluetooth device such as a smartphone.)

ESP32

ESP32 is a series of low cost, low power system on a chip microcontrollers with integrated Wi-Fi & dual-mode Bluetooth. The ESP32 series employs a Tensilica Xtensa LX6 microprocessor in both dual-core and single-core variations. ESP32 is created and developed by Espressif Systems, a Shanghai-based Chinese company, and is manufactured by TSMC using their 40 nm process.It is a successor to the ESP8266 microcontroller.

Features

Features of the ESP32 include the following:

• Processors:
  • CPU: Xtensa dual-core (or single-core) 32-bit LX6 microprocessor, operating at 160 or 240 MHz and performing at up to 600 DMIPS
  • Ultra low power (ULP) co-processor
• Memory: 520 KiB SRAM
• Wireless connectivity:
  • Wi-Fi: 802.11 b/g/n/e/i
  • Bluetooth: v4.2 BR/EDR and BLE
• Peripheral interfaces:
  • 12-bit SAR ADC up to 18 channels
  • 2 × 8-bit DACs
  • 10 × touch sensors
  • Temperature sensor
  • 4 × SPI
  • 2 × I²S
  • 2 × I²C
  • 3 × UART
  • SD/SDIO/MMC host
  • Slave (SDIO/SPI)
  • Ethernet MAC interface with dedicated DMA and IEEE 1588 Precision Time Protocol support
  • CAN bus 2.0
  • IR (TX/RX)
  • Motor PWM
  • LED PWM up to 16 channels
  • Hall effect sensor
  • Ultra low power analog pre-amplifier
• Security:
  • IEEE 802.11 standard security features all supported, including WFA, WPA/WPA2 and WAPI
  • Secure boot
  • Flash encryption
  • 1024-bit OTP, up to 768-bit for customers
  • Cryptographic hardware acceleration: AES, SHA-2, RSA, elliptic curve cryptography (ECC), random number generator (RNG)
• Power Management
  • Internal LDO
  • Individual power domain for RTC
  • 5uA deep sleep current
  • Wake up from GPIO interrupt, timer, ADC measurements, capacitive touch sensor interrupt

QFN packaged chip & module

ESP32 is housed in Quad-Flat No-leads (QFN) packages of varying sizes with 49 pads. Specifically, 48 connection pads along the sides and one large thermal pad (connected to ground) on the bottom.

Ampere

The ampere (symbol: A),often shortened to "amp", is the base unit of electric current in the International System of Units (SI). It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics.
SI defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier CGS measurement system had two different definitions of current, one essentially the same as the SI's and the other using electric charge as the base unit, with the unit of charge defined by measuring the force between two charged metal plates. The ampere was then defined as one coulomb of charge per second.In SI, the unit of charge, the coulomb, is defined as the charge carried by one ampere during one second.
In the future, the SI definition may shift back to charge as the base unit, with the coulomb defined in terms of the elementary charge on electrons and protons (one coulomb equals the charge of roughly 7018624200000000000♠6.242×10¹⁸ protons).

Fuse

In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, and it must be replaced or rewired, depending on type.
Fuses have been used as essential safety devices from the early days of electrical engineering. Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity and response times, depending on the application. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Wiring regulations usually define a maximum fuse current rating for particular circuits. Short circuits, overloading, mismatched loads, or device failure are the prime reasons for fuse operation.
A fuse is an automatic means of removing power from a faulty system; often abbreviated to ADS (Automatic Disconnection of Supply). Circuit breakers can be used as an alternative design solution to fuses, but have significantly different characteristics.

History

Breguet recommended the use of reduced-section conductors to protect telegraph stations from lightning strikes; by melting, the smaller wires would protect apparatus and wiring inside the building. A variety of wire or foil fusible elements were in use to protect telegraph cables and lighting installations as early as 1864.
A fuse was patented by Thomas Edison in 1890 as part of his electric distribution system.

Construction

 

A fuse consists of a metal strip or wire fuse element, of small cross-section compared to the circuit conductors, mounted between a pair of electrical terminals, and (usually) enclosed by a non-combustible housing. The fuse is arranged in series to carry all the current passing through the protected circuit. The resistance of the element generates heat due to the current flow. The size and construction of the element is (empirically) determined so that the heat produced for a normal current does not cause the element to attain a high temperature. If too high a current flows, the element rises to a higher temperature and either directly melts, or else melts a soldered joint within the fuse, opening the circuit.
The fuse element is made of zinc, copper, silver, aluminum, or alloys to provide stable and predictable characteristics. The fuse ideally would carry its rated current indefinitely, and melt quickly on a small excess. The element must not be damaged by minor harmless surges of current, and must not oxidize or change its behavior after possibly years of service.
The fuse elements may be shaped to increase heating effect. In large fuses, current may be divided between multiple strips of metal. A dual-element fuse may contain a metal strip that melts instantly on a short-circuit, and also contain a low-melting solder joint that responds to long-term overload of low values compared to a short-circuit. Fuse elements may be supported by steel or nichrome wires, so that no strain is placed on the element, but a spring may be included to increase the speed of parting of the element fragments.
The fuse element may be surrounded by air, or by materials intended to speed the quenching of the arc. Silica sand or non-conducting liquids may be used.

Characteristic parameters

Rated current I_N

A maximum current that the fuse can continuously conduct without interrupting the circuit.

Speed

The speed at which a fuse blows depends on how much current flows through it and the material of which the fuse is made. The operating time is not a fixed interval, but decreases as the current increases. Fuses have different characteristics of operating time compared to current. A standard fuse may require twice its rated current to open in one second, a fast-blow fuse may require twice its rated current to blow in 0.1 seconds, and a slow-blow fuse may require twice its rated current for tens of seconds to blow.
Fuse selection depends on the load's characteristics. Semiconductor devices may use a fast or ultrafast fuse as semiconductor devices heat rapidly when excess current flows. The fastest blowing fuses are designed for the most sensitive electrical equipment, where even a short exposure to an overload current could be very damaging. Normal fast-blow fuses are the most general purpose fuses. The time delay fuse (also known as anti-surge, or slow-blow) are designed to allow a current which is above the rated value of the fuse to flow for a short period of time without the fuse blowing. These types of fuse are used on equipment such as motors, which can draw larger than normal currents for up to several seconds while coming up to speed.
Manufacturers can provide a plot of current vs time, often plotted on logarithmic scales, to characterize the device and to allow comparison with the characteristics of protective devices upstream and downstream of the fuse.

The I²t value

The I²t rating is related to the amount of energy let through by the fuse element when it clears the electrical fault. This term is normally used in short circuit conditions and the values are used to perform co-ordination studies in electrical networks. I²t parameters are provided by charts in manufacturer data sheets for each fuse family. For coordination of fuse operation with upstream or downstream devices, both melting I²t and clearing I²t are specified. The melting I²t is proportional to the amount of energy required to begin melting the fuse element. The clearing I²t is proportional to the total energy let through by the fuse when clearing a fault. The energy is mainly dependent on current and time for fuses as well as the available fault level and system voltage. Since the I²t rating of the fuse is proportional to the energy it lets through, it is a measure of the thermal damage from the heat and magnetic forces that will be produced by a fault.

Breaking capacity

The breaking capacity is the maximum current that can safely be interrupted by the fuse. This should be higher than the prospective short-circuit current. Miniature fuses may have an interrupting rating only 10 times their rated current. Some fuses are designated High Rupture Capacity (HRC) and are usually filled with sand or a similar material. Fuses for small, low-voltage, usually residential, wiring systems are commonly rated, in North American practice, to interrupt 10,000 amperes. Fuses for commercial or industrial power systems must have higher interrupting ratings, with some low-voltage current-limiting high interrupting fuses rated for 300,000 amperes. Fuses for high-voltage equipment, up to 115,000 volts, are rated by the total apparent power (megavolt-amperes, MVA) of the fault level on the circuit.

Rated voltage

The voltage rating of the fuse must be equal to or, greater than, what would become the open-circuit voltage. For example, a glass tube fuse rated at 32 volts would not reliably interrupt current from a voltage source of 120 or 230V. If a 32V fuse attempts to interrupt the 120 or 230 V source, an arc may result. Plasma inside the glass tube may continue to conduct current until the current diminishes to the point where the plasma becomes a non-conducting gas. Rated voltage should be higher than the maximum voltage source it would have to disconnect. Connecting fuses in series does not increase the rated voltage of the combination, nor of any one fuse.
Medium-voltage fuses rated for a few thousand volts are never used on low voltage circuits, because of their cost and because they cannot properly clear the circuit when operating at very low voltages.

Voltage drop

The manufacturer may specify the voltage drop across the fuse at rated current. There is a direct relationship between a fuse's cold resistance and its voltage drop value. Once current is applied, resistance and voltage drop of a fuse will constantly grow with the rise of its operating temperature until the fuse finally reaches thermal equilibrium. The voltage drop should be taken into account, particularly when using a fuse in low-voltage applications. Voltage drop often is not significant in more traditional wire type fuses, but can be significant in other technologies such as resettable (PPTC) type fuses.