The Modiewark detects the presence of an alternating electric field. Its unique switching action allows identification of A.C. voltage levels from 110v to 750,000 volts.

This instrument consists of a 4.5v transistor amplifier diode lamp, audio buzzer and a sensitivity attenuator.
The Modiewark is used for checking the voltage on outdoor overhead conductors and indoor conductors.

All high voltage tests are carried out with the tester attached to an operating stick. The sensor plate in the cap is flat allowing directional checks such as checking low voltage when high voltage is nearby - the tester faces away from H.V.

Induced voltages on isolated conductors are checked by increasing the Modiewark sensitivity. Failure of the attenuator through a damaged switch or resistor will cause the tester to operate at full sensitivity.

Continuous self checking of the tester: The self checking is arranged by wiring pulses from the output to the input sensor plate. Standby pulses: The output to input pulses continually check each second: 1. Battery above 2.5 volts 2. Battery connections 3. Any fault within the tester

The one second between pulses will increase to 1.5 seconds as the battery ages.
Pulses are not emitted if the battery falls below 2.5 volts. These short pulses are seen and heard, live conductor indication is a full light and buzzer.