This electronic Morse Key for telegraph message transmission was found in an American 1980s amateur radio documentation. The circuit uses TTL technology and must be powered by a 5V voltage.
This circuit to increase the sensitivity of instruments to 100 uA (or close to it) was found in...
S1 changes the selection of the input signals in the circuit shown here. Other type of circuits,...
The circuit shown in Figure bellow generates frequencies of 50 Hz, 100 Hz, and 200 Hz. The circuit uses a...