Shared Projects by thespeakerguy

A simple circuit to turn on a battery powered fixture for about 5 minutes. Has soft start current limiting. Positive feedback makes turn off quick and controlled. Draws 0 current in off, 6µA when on at 4V.

Item Qty Ref Manufacturer Description 1 2 C2-3 Vishay 0.10µF ±10% 50V Ceramic Capacitor X7R Radial 2 1 C1 Cap, 470uF, ±20%, 10V, 6.3x11mm, TH 3 3 J1-3 IO Header 4 1 Q1 Microchip MOSFET N-CH 60V 300MA TO92-3 TN2106N3-G 5 1 Q2 On Semi MOSFET P-CH 20V 24A TO-220, NDP6020P 6 1 R2 100 ohms 7 1 R4 100k ohms 8 1 R5 10M ohms 9 2 R1 R3 1M ohms

Low Power Continuity Beeper Uses LMV614 Quad op amp. Runs on 2or3 x AA down to 2V Drives 8Ω Speaker Output frequency is function of test impedance. Short is about 200Hz.