This circuit activates a warning lamp when an incoming call is received. We found it in an 80s Hands-On Electronics. The diac and triac can be of any type.
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...