This circuit was found in a 90s Popular Electronics. The circuit uses 4 bicolor LEDs to indicate signals of both TTL and CMOS logic. The circuit is powered by the source of the circuit under test.
The operational amplifier of this balanced circuit is old and can, however, be implemented with...
This SSB modulator does not use the balancer transformer. The circuit is from an 80's...
In the figure we show a configuration for a crystal controlled overtone oscillator using a...