This turntable filter was found on an 80's Elektor. The circuit makes use of operational features that are easily obtainable today.
This trigger-delay circuit was found in a 1960s General Electric unijunction transistor manual. The...
We present the circuit of the commercial transistor tester Sanwa SC2 sold in Japan in the 1960s. The...
This receiver for a modulated light intercom was found in a 90s Elektor. The audio amplifier can be...