A while back, I wrote an article on how to use a CP2102 USB/UART converter chip in place of an FT232RL to program an ATmega328P using Arduino bootloader. Of course, not everyone has the time or wants to build one…
HP 436A is a power meter capable of measuring RF power between -70 dBm and 44 dBm (roughly between 0.1 nW to 25 W) with a frequency range from 100 kHz all the way upwards to 110 GHz depending on…
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,…
One way to extend the resolution of a digital-to-analog converter (DAC) is by employing a sigma-delta converter in software. The main disadvantage of such approach is the slow speed. Alternatively, we can use some extra hardware to extend the usable…
I was doing a project that needed a driver for hard disk spindle motors. While I could use a microcontroller to generate the required driving waveform sequence, keeping the waveform in sync with the motor rotation is actually quite tricky…
Getting a rough measurement of the transistor hFE’s is useful when designing analog circuits. Unfortunately, only the lower end DMMs nowadays offer such functionality as it is becoming less and less useful to measure transistor hFEs in a world that…
I bought a couple of Peltier cooler modules on eBay a while ago for some experiments. Of course, as I expected the quality of those cheap modules were pretty poor. After a couple of hours of continuous operation, both modules…
In part 1 of this series of blog postings, I showed my preliminary design of a dual tracking linear power supply. In part 2, I showed the completed design and also the finished power supply circuits. And as promised last…
In my previous post, I showed my design of a dual tracking ±30V linear power supply. My goal was to use the transformer (28V+28V, center tapped) from an old Deltron W127G open-frame power supply and build a lab supply that…
Power supply is one of those things one can never have too many of. I have quite a few already, and my favorite one so far is the Topward 6603A. This dual 60V/3A tracking power supply satisfies most of my…
A while ago, I built a precision voltage adapter using LMP8358. In this post, I will show you a similar precision voltage adapter built using a Linear Technology‘s LTC1100.
A while back I built a simple constant current electronic load using an aluminum HDD cooler case as the heatsink. While it was sufficient for a few amps’ load under low voltages, it could not handle load much higher than…
Arduino‘s (ATmega328P) PWM outputs via analogWrite can be conveniently turned into analog voltage levels through the use of simple RC filters. Since the PWM outputs are not isolated, using them to drive other devices directly could be potentially dangerous. This…
One of the things I love to buy from eBay is linear power supply. Labs and industries routinely clear out older power supplies and many of them end up on eBay. And unlike many other used electronics, linear power supplies…
In my previous post, I showed my design of a semiconductor V/I curve tracer and discussed its theory of operation in detail. As promised, I will share some of the test results here. If you have not read my previous…