Found in the December 1974 issue of Radio Electronics, this circuit is similar to the previous one, only using another TTL counter. The circuit must be powered by 5 V.
This circuit was found in a 1977 Radio Shack documentation. The unijunction transistor can be...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
This circuit offers excellent sound quality for headphones of 150 ohms or more. The circuit was...