Remote control tester (CB7823E)

This circuit from a 90s Electronics Now, uses a 4010 gate as a signal amplifier. The circuit triggers an indicator LED.

DTMF decoder (CB17454E)
The integrated circuits used in this 1999 project are not very common today. However, they can be...
Digital thermometer with the TL505 and TL502 (CB16050E)
This 3-digit thermometer, suggested by Texas Instruments, uses 3 integrated plus the display, with...
200 MHz Amplifier (CB14623E)
This circuit is from the National Semiconductor FET Databook. The coil data is provided with the...