This commercial radio with 3 earphone listening transistors was manufactured in Japan in the 1960s. The medium-wave circuit uses germanium transistors and is powered by a 9 V battery.
This other high stability thermocouple amplifier uses an 80's operating. The circuit can be used...
The mains cables work as antennas. We can take advantage of them with this circuit that consists of a...
This circuit was found in an American magazine in 1976. It doubles the frequency of TTL signals in the...