new to electronics and need help.....

Trying to make a target game. want to use a micro switch to initiate a circuit which will set off a buzzer and light a bulb as an indication that teh target was hit.
Problem, as the micro switch only completes the circuit when depressed, I want the light and buzzer to stay on for approx 2 secs. I have tried to incorporate a capacitator which didn't do the job. Have been told to use a NE555N, which I have obtained, but havn't got a clue how to incorporate it into the circuit to make it work... can anyone help..

Posted by gordon1 (gordon.cork@virgin.net) on 08/09/2006, at 22:54 GMT

555 monostable

The NE555N timer needs connecting as a monostable with a time period of about 2s. For details see Articles... Digital Electronics... 555 monostable. Use your microswitch as the trigger switch. For a 2s time period try R=180k and C=10µF, adjusting the value of R if necessary.

The 555 output can supply up to 200mA which is enough for some small lamps (6V 60mA is a popular type). I would also consider using an LED (and resistor) because modern ones can be large and bright. For more than 200mA you can use a transistor or relay on the output.

Posted by John Hewes on 12/09/2006, at 10:08 GMT