Found in a 90’s American documentation, this circuit indicates the frequency of input pulses up to 1 kHz. The circuit has a very explored configuration on this site.
This circuit was originally designed with the operational 747 which is rare today. However, the...
This circuit was found in a 1975 technical publication. The circuit can be designed with 741...
The TDA2613 is the mono version of the TDA1521A and has pinouts compatible with an integrated...