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 circuit was found in documentation from the 1980s. The integrated circuit used is uncommon today...
This audio oscillator configuration appears in many of our circuits and even in this section from...
This Linear Technology circuit charges a battery from the energy produced by a wind generator that can...