The circuit shown consists of a power stage for relay excitation. 2N3053 can be a BD135 and 2N406 can be replaced with a BD136. R3 depends on the trigger voltage.
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...