Found in National Semiconductor documentation, this logarithmic meter is powered with a voltage of only 1.5 V. Equivalent operational amplifiers can be tested.
The 556 consists of a double integrated circuit 555, which can be replaced by them in this...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This circuit is from American documentation from 1970. It can be designed with a BC558 and for the...