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.
The resistors on this circuit from an American publication from the 70s are 220 ohms. The circuit...
This filter is inserted between the interfering device and the interfering device. The coils are...
This logic circuit can indicate both TTL (5 V) and CMOS (5 to 12 V) output levels, operating with...