Found in an Elektor from the 90s, this circuit is suitable for viewing audio signals on an oscilloscope. The operational amplifier admits equivalent.
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...