KA431/TL431 Time Delay Switch
The real inspiration for this post actually came from lots of lame designs seen on the web. The last drop was a reasonably great written article presenting a number of blueprints to build timer circuits […]
BEMF and DC Motor Speed Governors
Do you know? You can govern the speed of brushed DC motors without any additional sensors, but using a basic characteristic – the speed-dependent back EMF (BEMF) voltage! The BEMF motion control technique has been […]
Poor man’s Car Power Probe
You do not need to read this post if you are willing to thoughtlessly throw away your hard-earned money to buy a car power probe that only has very cheap electronic circuitry inside. On the […]
BBC micro:bit Dark-Activated LED Badge
As promised, here is another fun BBC micro:bit project for your lovely kids. This time, get ready to make a dark-activated LED badge for them and enjoy! By now hopefully you have already gone through […]
741 Op-Amp Cookbook for Beginners (v1)
This post is about the far-famed and widely-used 741 classic operational amplifiers! While not attempting to share numerous potential applications, it includes one basic circuit idea that can be tweaked well to applications other than […]
Safe Car Power Socket v1
Now get ready to make your own safe car power socket using inexpensive components that are generally available. The simple device can then be used as a safe accessory power outlet to extend the 12VDC […]
Improved Door Security Monitor Switch
Nowadays, there are various types of switches available to help you track whether your door is open or closed. Such a door status monitor switch changes its states when the door is opened or closed. […]
hFE Test Connector/Adapter for Analog Multimeter
As mentioned in my previous post, some analog multimeters offer the hFE test feature via a custom-made hFE connector that is usually sold as an optional accessory. The popular Sanwa YX-361TR analog multimeter is a […]
Poor man’s Transistor Beta (hFE) Tester
The hFE socket on most cheap digital multimeters provides a dc gain value (often simply pointed as β) useful for evaluating small signal silicon transistors. However, only a few multimeters with the quick NPN/PNP transistor […]
Poor man’s 500kHz Oscillator
This post demonstrates an example of a cheap ceramic resonator based 500kHz oscillator. You can consider this a more practical version of my previous post on this topic Learn To Play with Ceramic Resonators The […]