We can send and receive commands wirelessly with Arduino by using these cheap RF data link transmitters/receivers. I like these RF modules because they can be hooked up to pretty much any device that supports serial communications (e.g. devices equipped…
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…
TI’s TLV5620 is a budget 4-channel 8-bit DAC. While it is designed primarily for running with a power supply between 3V and 3.6V, it can be powered by 5V as well given its wide supply voltage range. With a TL431…
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…
Semiconductor curve tracers were frequently used in analog circuit designs many decades ago, at a time when discrete semiconductor devices were in dominance and ICs were scarce. While curve tracers are no longer widely used nowadays due to the ubiquity…
Most offline/line interactive UPS‘ (Uninterrupted Power Supply) have a transfer time between 5 to 15 milliseconds. In this post, I will show you the results of the measured switch-over performance of my APC Back-UPS XS1500 and the technique I used.
I love old Tektronix analog oscilloscopes and I could not seem get enough of them. So when I saw a cheap “untested, unknown working condition” Tektronix 2213 listed on eBay recently, I just could not resist the temptation to grab…
I typically use linear regulators (e.g. 7805, LM317, etc.) in my projects. Linear regulators (especially the low dropout ones) are great when the load is light and input/output voltage difference is small, otherwise you will need a big heatsink as…