This is an simple op-amp IC tester circuit that cheap and easy to build. for test many op-amp ICs fast check. for LM741, LM324, LM339, LM358, LM311 and more [...]
This Diode tester circuit can check the diode the good or bad and also can indicate its polarity. using op-amp 741IC and LED for display. [...]
This is Crystal tester circuit using NPN transistors as main. LED1 is light up when a crystal is good and simple oscillator circuit works.
Normal multimeter cannot check it. This circuit can help you.
This is the Transistor tester circuit into PCB. When your project do not works, the tester electronic parts or component be what need very much.
This is Coaxial cable tester circuit,to check the cables inside and outside. Check the continuity,short-circuited,detect high resistance, By show with LED [...]
This is 555 audio simple ohmmeter circuit. Some times, we need to measure roughly resistances only. we can know resistances by audio also fast check. [...]
