This interesting circuit uses a sodion valve that we have already described in an article on the website. The circuit uses several batteries for power. The phone is of high impedance.
This tone-modulated transmitter was found in recent English documentation. The circuit operates in the 27...
This simple CMOS digital game was found in an English publication in 1992. The circuit uses a...
This good quality stereo amplifier was found in a Japanese publication from the 1960s. The circuit...