Voltage phase or polarity detector - utilises miniature gas discharge lamps which also indicate approximate amplitude

摘要

The voltage sensor signals the presence of an AC or DC voltage and indicates its phase or polarity. Indication is given of the approximate value for its use in maintenance of installations. The detector comprises a panel with windows in which miniature gas discharge lamps (L) are visible. A separate lamp (L6) flashes to indicate phase when a probe (12) is connected to earth. Two other probes (3, 4) connect to the lamp circuits which are powered in parallel by resistive voltage dividers (R2-10). Diodes (D1, D2) enable the voltage polarity to be indicated and a bell circuit (13) gives audible indication that AC voltage is present.