This circuit was found in a Philips documentation from 1966. The circuit provides 1 mW with a power supply of only 1.3 V. Transistors support current BC series equivalents.
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...