This circuit was found in a 1985 documentation. It provides an audiovisual indication of the presence of moisture or water in the sensor. The circuit can be powered by voltages from 6 to 9 V.
This protection circuit for standing waves was found in a manual of high frequency circuits and...
This high input impedance amplifier stage was found in a 1963 documentation. The transistor...
This setting appears multiple times on the site from different sources. This is from a 2000 manual...