Modulator for rectangular signals (CB21630E)

Based on TTL logic this circuit can vary both the frequency and the pulse width of a rectangular signal. Equivalent components can be tested.

| Clique na imagem para ampliar |

CMOS Oscillator (CB25040E)
This circuit is from Radio Electronics from February 1987. The frequency is given by the crystal that...
LASCR Controlled Oscillator (CB13888E)
In this circuit, a light-sensitive SCR or Light Activated SCR determines the operation of an...
Hearing Aid Amplifier (CB21798E)
This 3-transistor circuit was found in a Mullard manual from 1960. The transistors are germanium of the...