Description

The objective of this project is to design and install an electronics timer circuit for staircase lighting This is a push-to-on, and auto-OFF circuit. User needs to push the button only ones: to turn the light on. The light will turn automatically OFF after some time, since the switching OFF mechanism is timer based. The "push to on" switch is used here; this should be momentarily pushed to turn the light on. When "push to on" switch is pushed, pin-2 gets a negative pulse, and the timer gets triggered. and the IC1 555 output voltage at pin 3 will be high for certain time period, T=1.1RC, energizing the relay and so closing its contact to provide supply to illuminate the lights for that period. At the end of the time period the IC1 555 output voltage at pin 3 will be low, and so de-energizing the relay and so its contact will open cutting the supply and turning off the lamps The book consists from the following parts: 1. Introduction 2. Circuit components: 555 and 556 Timer Circuits, Relays and Transistors 3. Description of the Project: Main circuit components, circuit description, selection of R and C according to required time period, settings, designed Circuit 4. Conclusion 5. References