Schematic & Wiring Diagram

Photo Timer Circuit with 555 Microchip Circuit Diagram

Time is set by potentiometer R2 which provides a ambit or 1 sec. To 100 abnormal with timing capacitor C1 of 100uF. The achievement at pin 3 is commonly low and the broadcast is captivated off. A cursory advance on about-face S1 energies the broadcast which is captivated bankrupt for a time 1.1 X (R1+R2). C1 and again released. The exact breadth of the timing breach will depend on the absolute capacitance of C1. Most electrolytic capacitors are rated on the base of minimum affirmed amount and the absolute amount may be higher. The ambit should be calibrated for assorted positions of the ascendancy bulge of R2 afterwards the timing capacitor has had a adventitious to age. Once the capacitor has accomplished its abiding value, the timings provided should be able-bodied aural the accurate requirements.

Photo Timer Circuit with 555 Microchip Parts List :

C1 - 100uF, 25V electrolytic
C2 - 0.01uF, disc ceramic
D1, D2 - DR50 or 1N4001
R!,R2 - 10K ohms, ¼ watts
R3 - 1 M ohms, potentiometer
RLY1 - 12V, DC relay, operating current less than 200mA
S1 - Push-to-on switch
U1 - NE555 timer IC

P1 & P2 are for exposure lamp ckt.