This 80's Exar circuit has a carrier detector for frequencies up to 500 kHz. The circuit uses a company 567 which is still a common component.
This amplifier has a few Watt output, using old transistors. The speaker is 45 ohms, but with...
This circuit was found in an 80's Electronic Design. It amplifies TTL fast signals for a coaxial...
This circuit uses a Norton operational amplifier to generate 1 kHz pulses with a 1 to 60...