Kerry Wong writes:
Transistors operating in their avalanche regions are often used to generate fast rise pulses (see avalanche pulse generator using 2N3904). Many transistors can also avalanche when the connections to collector and emitter are reversed. When operating in reverse avalanche region, these transistors are sometimes referred to as negistors.
Because the asymmetry and doping differences between the base-emitter and base-collector junctions, the avalanche voltages for reversely connected BTJs are usually magnitudes lower than their normal avalanche voltages. Here, I decided to test a few different transistors and see at what voltages the reverse avalanche occur.
The circuit I used is a simple LED flasher, similar to what was described here. As with any circuit that exhibits negative differential resistance, the principle of operation is quite simple. The capacitor is charged via a current limiting resistor…
BJT transistor in reverse avalanche mode - [Link]
Allegro MicroSystems, LLC have announced a new synchronous buck converter with low RDS(on) internal impedance capable of delivering a current of 8 A. The A8672 utilizes valley current mode control, allowing very short on-times to be achieved. This makes it ideal for applications requiring very low output voltages, relative to the input voltage in combination with high switching frequencies.
Valley current mode control gives improved transient response compared to traditional switcher schemes, through the use of a voltage feed-forward loop and frequency modulation during large signal load changes. The A8672 also provides a set of diagnostic flags allowing a host controller to respond to a number of different fault conditions. A fault output indicates over-temperature or single-point failure detection which could indicate switching node (LX) shorted to ground, or the timing resistor going open-circuit. A Power OK (POK) output is also provided after a fixed delay, to indicate when the output voltage is within regulation. A selectable pulse-by-pulse current limit avoids the need to oversize the inductor to cope with large fault currents.
Allegro’s A8672EEGTX-T is targeted at the industrial, consumer and computer markets and is available in a 4 mm x 5 mm, 28-contact QFN (suffix EG) with exposed pad for enhanced thermal performance.
Small 8 Amp Buck converter - [Link]
The “EasyPlug Shield” for Arduino makes it super easy to connect sensors to your Arduino. The EasyPlug shield provides an incredibly simple, clean, and quick way to connect sensors to your Arduino board. They have sensors for just about anything.
All of our sensors are designed to be easy to use, right out of the box. Plug in a cable (provided) and the sensor is ready to go. We’ve picked the most useful and fun sensors for you. But we’re adding more all the time, so you should be able to find a sensor to fit your needs.
EasyPlug: The Sensor Shield for Arduinos - [Link]
Do you have an application where a black switch is not suitable? We have an elegant white one for you.
Rocker switches are available in a vast majority in a black version. When we take a look at catalogues of renowned producers we´ll usually find there mainly black types and only a few white ones. However a switch in a black version can be advantageous in many applications like office devices, PC, “white” (home) goods, lighting, equipment, but also in many other devices having enclosure other than black, or where just a white version can be an interesting design element. Even in our electronic branch it´s particularly true, that a “package sells” and an aesthetic design of a device can be one of the factors of a market success.That´s why you can find in our stock two novelties – a white rocker switch 1832.3311 ((DPST, 20A/250VAC) as well as a round 1881.1105 (SPST, 12A/250VAC). Both novelties belong to well proven series with widely known properties. Detailed description can be found in 1830 and 1881 series datasheets.
Recently we added into our standard stock offer also many other types from Marquardt and you can find them below this article.
Black or white? - [Link]
Using LTM8031 integrated circuit, manufactured by linear technology, can be designed a very simple high efficiency dc dc converter circuit. This LMT8031 dc voltage converter circuit will provide a 5 volts output from a wide input voltage range between 7 and 36V dc. The switching frequency range of LTM8031 is from 200kHz to 2.4MHz which can be set by a single resistor. To finish the design of the LTM8031 are needed only the bulk input and output filter capacitors . Main features of this ic based dc converter project are: Complete Step-Down Switch Mode Power Supply , Wide Input Voltage Range: 3.6V to 36V , 1A Output Current , 0.8V to 10V Output Voltage , Switching Frequency from 200kHz to 2.4MHz , EN55022 Class B Compliant , Current Mode Control. Maximum output current of this circuit is around 1A.
LTM8031 – 5v 1A DC/DC μModule Regulator - [Link]
In this episode Shahriar reviews and demos the second revision of the industry’s first Mixed Domain Oscilloscope from Tektronix. The MDO4000B series offers improved signal integrity and performance. The reviewed model is a MDO4104B-6 which offers 16-Channel Logic Analyzer, 4-Channel Oscilloscope with 1GHz of analog bandwidth as well a 6GHz Spectrum Analyzer with greater than 1GHz of instantaneous capture bandwidth with 65dB of dynamic range.
After an overview of the instrument’s interfaces and built quality, the block diagram and principle operation of the instrument is explained. The time-correlated digital, analog and RF capturing capability is described and its advantages for debugging complex mixed-domain systems is explored. Instrument probes, accessories and various modules are also presented.
Tektronix MDO4104B-6 Mixed Domain Oscilloscope (MDO4000B) Review and Experiments - [Link]
Small USB development board for Android. Smartphone powered, USB 2.0 communication, direct connection, open sourced API.
It’s an ARM Cortex-M3 development board that connects directly to your Android smart phone micro USB port. It’s powered from the phone so it has enough power for all sorts of applications without extra batteries, and when the device is connected to the phone the appropriate application starts up automatically.
USB2Go – Android Devices Everywhere, Arduino Extendable - [Link]
Nixie tubes need about ~180Vdc to light up and thus on most devices a DC-DC converter is needed. We designed here a simple DC-DC switching regulator capable of powering most of Nixie tubes.
The module is based on the MAX1771 Step-Up DC-DC Controller. This controller works up to 300kHz switching frequency and that allows the usage of miniature surface mount components. It accepts an input voltage from 2 to 16.5V and the output is factory configured to 12V. In this module the output voltage is configured higher at ~180Vdc using external resistors and a potentiometer.
HV Nixie DC-DC Power Supply - [Link]
µ-Wire: USB on ATtiny10 controlling a WS2812 LED. cpldcpu writes:
I tried to push the ATtiny10 to its limits and succeeded – I implemented a seriously gutted version of V-USB on an SOT23 ATtiny10 with just 1kb flash and 32b of RAM. It implements a subset of the little-wire protocol to control a single WS2812 LED.
µ-Wire: USB on ATtiny10 controlling a WS2812 LED - [Link]
Water, dust, mud, chemicals,… multi-pole industrial connectors Hirschmann CM will handle it easily.
Plastic- or a metal connector? Majority of designers will probably place on the first place in a virtual “quality chart” a connector with a metal body. It´s often true, but it needn´t be always so. Apart from the fact, that a metal connector is usually more expensive, often – mainly in a corrosive environment a metal body isn´t advantageous. Modern high-strength plastics, often glass-reinforced reach strength fully sufficient to create a rigid and reliable connector. This can be seen for example in connectors from company Hirschmann (a member of Belden group) CA3 or CA6 series, which we introduced to you in our article A connection resistant to dust and water – Hirschmann CA series and also in multipole connectors CM series, which we´d like to introduce to you in this article.
CM series is in general very similar to the CA series as for the design, robustness and materials used. Connector body is from the fiberglass reinforced polyamide, contains silver-plated contacts and has IP rating 67. Also range of operating temperatures is very high – from -40 to +90°C.
Main difference is, that these connectors are compatible to MIL-C 5015 resp. VG 95 342 and are available with 4-17 poles (4,5,6,6+PE,7,14,17). All versions of the CM series handle 50V AC/DC and 4-10A currents, depending on the type. CM06 are F connectors (socket) for a cable and mating types are CM02E – i.e. Male panel connector. The only exception are connectors CM02L (6 poles+PE) with a metal body. Also available are CM02SD covers and a sealing CM02D.
Detailed information will provide you datasheets at particular types and a list of available types can be found in the Hirschmann catalogue.
“17 in 1″ – these are the multi-pole connectors Hirshmann CM - [Link]