Found in Motorola's 1967 documentation this circuit can use any general-purpose transistor. The signal should be applied to a good amplifier. The noise diode can be replaced with a common one.
This circuit is for a siren that can be used with any of the above alarms and also other types. The...
In the figure we have a way to adapt a phone obtained to the output of a common amplifier. The...
Found in an old Popular Electronics, the sparker is driven by a motor being adapted to the...