This circuit with 4 transistors can receive signals in 6 shortwave bands. The circuit is from a Radio Electronics from May 1958. The output is for high impedance headphones.
Found in a 90s Popular Electronics, this circuit is based on a uA739, an unusual component today....
This circuit is from a 1982 publication. It is a sequential effect of accelerated LEDs. The...
In the figure we have more circuit that makes use of transistors and that has excellent...