This circuit was found in a 1975 documentation. The SCR can be of any type and in this case, we have the horn activation. The relay must be a 12 V type with high contact current.
We found this high gain circuit with the LM381 preamplifier in a Radio Electronics from February 1990....
We can produce pulses controlled through this circuit that can function as a shield if powered by a...
If mounted with SMD components, this transmitter will be so small that it can be installed inside a...