Light source control circuit - uses power monitoring circuit to regulate conduction factor or firing angle of controlled semiconductor

摘要

The circuit (DT) contains an oscillator (8) which is connected to earth (10). It operates at 50 or 60 Hz and is connected to several capacitors, (6, 9, 11). The first capacitor (6) is connected to the drain of a first FET (1) and a second FET (12); it is also connected to a self-oscillating circuit (4). The source of the first FET is polarised by a resistor (2) which is connected in parallel with a capacitor (3). The circuit is used to turn on a light by acting as a touch switch. The terminal (7) connected to the first capacitor (6) may be connected to the metal casing of a torch or lighting unit. Potentials (OV) and (+12V) may be furnished via a diode bridge. The circuit contains a third transistor (14).