This circuit that can be activated by light or heat was found in an old American documentation, but the components it uses are perfectly current. The power transistor shall be fitted with a heat sink.
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...