The circuit presented is a Japanese commercial radio from the 1960s. With a 4.5 V supply, it is a super-heterodyne type with an IF of 455 kHz. 6 germanium transistors are used.
Found in Radio Electronics this circuit uses a fotodiac to drive a triac. The circuit can use...
This circuit is from an old English documentation. It is intended for coupling a microphone to the...
Here is an interesting circuit to be used in physics demonstrations involving energy...