This amplifier step for small signals can use any general-purpose transistor like the BC548. The circuit can be powered by voltages from 6 to 12 V.
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...
) Suggested by Philips in a 1968 documentation this circuit has very high 10 ohm on-load voltage...
No information is given about the transformers in this circuit suggested by Motorola in a 1968...