This 1965 circuit uses a Philips 4068 tube to measure extremely small charges. The circuit has as indicator a micro ammeter and the transistors are of the time.
This triac temperature control circuit was found in an 80s power semiconductor documentation. The circuit...
Figure bellow shows how n flip-flops can be associated to perform a shift register. Data is...
This circuit is from 1986 documentation, being adaptable in radios of that time. The circuit uses the...