Free Circuit Diagram

Metronome is very important tool if you studying music playing. There are mechanical metronome device in the past, but today, electronic metronome is much more popular since it can be very simple, compact/small, reliable, and also has the most interesting feature: cheap. Here is one example of the electronic metronome schematic: Parts: [...]

Building electronic circuit tutorial (DIY: do it yourself project) is presented in this video. You can learn the basics about schematics and how they are used in electronics in this free home maintenance video.

Tired replacing your power supply fuses, or it cost too much because too often to blow? Use this electronic fuse and your life would be easier. It is good for your new power supply design, or you can just add it to your old power supply unit. This fuse has real fast response because it [...]

Notch filter is known as band-cut filter or band-reject filter. The fuction of this filter is to remove some frequency portion of a signal. The schematic diagram of this filter circuit, a second order notch filter is depicted in the figure below. The formula is actually complicated, but by taking the R3=R4 and [...]

How to solder a resistor to PCB is presented in this video tutorial, get expert tips and advice from an expert on how to solder electronic equipment in this free instructional video. Expert: Jeff Nayl…

Using a single supply quad comparator LM339, LM239, LM2901, LM2901V, NCV2901, or MC3302, we can build a square-wave oscillator with simple circuit and formula. Here is the schematic diagram: This circuit is suitable if you need  many square-wave oscillators in one circuit, since the quad packaged comparator provide four comparators in one single  [...]