This high-impedance headphone circuit was found in a 1990s William Sheets. The power is low, but the high input impedance makes it useful for radio applications.
This circuit was originally found in a Philips documentation from 1969. It is intended for sensing...
This 6-transistor transistor radio is a RCA product from the 1960s. The circuit is powered by a 9...
We found this circuit in documentation from the 90s. Instead of a voltmeter, you can use the...