This circuit that uses a loop antenna was found in a 1924 publication. The circuit has several supply voltages and sets of audio and RF coils.
This circuit was obtained from an Electronics World of 1969. General-purpose transistors can be...
This circuit is for a siren that can be used with any of the above alarms and also other types. The...
We found this circuit in a 1997 documentation. It uses a common analog indicator, measuring...