This circuit is from a 1980s Signetics documentation. The circuit separates the modulation signal from a carrier. The used components are not common today.
PIC18F “K40” Features Intelligent ADC with Filtering and Signal Analysis Capabilities Ideal for...
This circuit can be used as a buzzer from 3 different locations, allowing you to identify where it went...
This amplifier for public address was found in English documentation from 1967. The transistors are from...