This interesting digital counter with relays with complementary outputs was found in the Radio Electronics magazine of October 1961. The supply voltage is in accordance with the relays used.
This adapter circuit was found in a 1990 documentation. It is possible to connect a telephone line...
This receiver circuit was found in a Hands On Electronics from the 90s. The circuit uses a PLL...
The operational amplifier of this low current source may be any of the JFET type. The output...