6 LED voltage indicator circuits
This is four circuits of LED voltage indicator are simple and easy to builds for check voltage battery and others, use as zener,transistor,LM339 and more
Include: Volt meters :: Sound level meter :: Analog vu meter :: Soil moisture meter :: Digital meter circuit diagram :: Temperature measurements :: Electronic measurement tools :: Frequency meters :: Best battery tester :: Transistor tester project
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This is four circuits of LED voltage indicator are simple and easy to builds for check voltage battery and others, use as zener,transistor,LM339 and more
The simple low voltage tester circuit using LM339,can use Battery voltage monitor for voltage sources that problems, by LED display and alarm sound.
Sometimes, we need to measure a too tiny AC voltage level. And high frequency too. Ohh… We cannot use general multimeter. I recommend you try watching the AC millivoltmeter circuit. It includes the 6 ranges. Lowest is 15mV only. Also, it uses an analog meter form. So, you can watch easily a slow changing of … Read more
This is simple signal injector circuit, used two transistors join together as astable multivibrator, signal output frequency 1,000Hz in square wave form.[…]
This is a Simple Refrigerator Door Alarm circuit, it will detect light of lamp in the fridge and alert with buzzer.Small size, easy to make and cheapest. […]