This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
Originally designed for WWV (Standard Time Station) signals, it lets 1 kHz tones pass by rejecting...
This circuit is inserted in series with an incandescent lamp causing it to flash at a frequency...
This circuit locks after a short touch on the sensor. The circuit can be powered by voltages from 5...