This siren configuration found in a documentation from the 1980s can also be seen in many of our projects and in this circuit bank. Transistors are common, but Q2 can be of power for a higher voltage supply.
We found this circuit in an English publication from 1980. It provides a logical output signal when...
With the circuit shown, we have an excellent level for the signal obtained from an electret...
The circuit presented was found in a documentation from the 1950s, generating a sinusoidal signal...