The voltages in an adjusted range in the trimpots are indicated by 3 LEDs. The LEDs indicate when the voltage is below the range, above the range and in the range.
The circuit found in a documentation from the 90s allows capacitance measurements to be carried out...
This circuit uses the LT6106 from Linear Technology, from where we took it from a 2005 manual....
September 2017 - Littelfuse's Polyswitch SMD Resettable PTCs can now be purchased from Mouser...