This 6-transistor Japanese commercial radio was manufactured in the 1960s. The receiver is a super heterodyne type with germanium transistors and is powered by a 9 V voltage.
This circuit is used to detect PLL signals from the 4046 IC. The circuit is from an Electronics Now from...
This amplifier or stethoscope with headphone output and using a crystal microphone was found in a...
This circuit uses an 80's operational amplifier. The circuit is from an old RCA manual and can be...