This amplified speaker is from a Radio Electronics from September 1988. The power integrated circuit is from that time and the other components are still common today.
Capacitance to voltage converter (CB6075E) This Texas Instruments circuit can be used on a...
This circuit was obtained from an American 80's documentation. The transistors can be 2N2222 and...
This circuit is a small FM transmitter, capable of carrying its signals over short distances...