Electronics Design

ESR meter DIY

One way to test electrolytic capacitors is to measure their capacitance. It does not tell the whole story of capacitor condition. Another usually more useful way to measure electrolytic capacitor condition is to use an ESR meter. Here is ESR meter I built years ago based on instructions from http://ludens.cl/Electron/esr/esr.html but I built the transformer

DT830 multimeters

Saw in Facebook discussionhttps://www.facebook.com/groups/electronichobycircuits/permalink/3657982357559780/ https://www.facebook.com/438304376511718/posts/1304575383217942/ Another meter is fried again today!!! I have six meters blown in 2 years, while reading high voltage AC. I guess I will find a better alternative for such reading. Is there a way of fixing spoilt meters!?. We are talking about this kind of DT830 type multimeters: My answer:

Linear power supply rectifier designer

LINEAR POWER SUPPLY DESIGN ASSISTANT #1 at https://www.changpuak.ch/electronics/power_supply_design.php is a tool for designing and simulating linear power supply rectification and smoothing capacitors See the circuit diagram. Enter the design data and can see the output voltage ripple and current on circuit. You can try with different capacitor values, different loads and different transformers. This is

Night light teardown

Here is a teardown of cheap mains powered LED night light from LIDL. After few years of use this light became very dim and so useless. I opened it to see what is in it and what was broken. Let’s open it. Circuit board details Here is the circuit diagram. This is quite typical transformerless

FPGA dev boards

An FPGA Developer’s Guide to Cheap Development Boards https://www.hackster.io/news/an-fpga-developer-s-guide-to-cheap-development-boards-8f1782bb271a Finally, a detailed and all-encompassing guide for those of us with an addiction to buying new FPGA development boards. Joel Williams’ list starts off by outlining the criteria that he looks for in an FPGA development board. He makes the great point to consider what peripherals

Mains surge suppressor teardowns

I saw a request for circuit diagram in Facebook electronics group: Hello feds. Required surge protector circuit. Working on 220v. 50hz 10amps load. I first offered this reverse engineering of one commercial mains surge protector “Ahlstrom 23 368″. The manufacturee component codes of the exact components used. S20K250 is a varistor for 250V AC /

Short circuit protection relay circuit fail

I saw at Facebook a video 12 v Short Circuit Protection and same for 220 volts (https://www.facebook.com/108281974135756/posts/166052965025323/). It was advertised as a short circuit protection relay circuit that will turn off the power when output is short circuited. This seems to be a quite popular circuit idea, because I saw several very similar circuit designs

Dirt cheap frame grabber

This is a story of a a video digitizing circuit I built early 1990′s. It kind of worked, but was not practical then and much less useful nowadays. It is an interesting how simple circuit could be used for converting analogue composite video signal to digital for computer processing. This is the story of Dirt

My DIY lab power supply

An adjustable regulated power supply is a necessary tool for an electronics laboratory. Here is a laboratory power supply 2.7-30V up to 4A I built has worked for 30 years ago and still going strong. Its function is to supply a stable voltage set by the voltage control potentiometer up to the current set by