This 6-transistor commercial radio with 6 V supply was found in a Japanese publication from the 1960s. The circuit is a commercial superheterodyne with 150mW to 200mW of battery powered output.
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...