This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American documentation for radio amateurs of the 80's. Equivalent component can be used.
This simple musical instrument was obtained from a 1967 magazine. If the original transistors are...
The transistor of this circuit can be the BC558. The circuit is from an old documentation...
We found this circuit in an old American documentation for hams. The circuit serves as a telegraph...