Found in 1967 documentation, this circuit makes use of period transistors and drives a common light bulb. Nothing against it being adapted to use LED.
We found this circuit in an internet documentation. The circuit uses a 1 mA instrument, and the...
This circuit can be used to measure the frequency of a low frequency square signal. The signal can be...
This circuit is from 1985 documentation. The integrated circuit used is not very common today, but...