??? 01/28/06 17:14 Read: times |
#108610 - ICM7555 + 2M2 + 6µ8 Responding to: ???'s previous message |
Suresh said:
The time(0 to 10 sec variable) is being set using a potentiometer arrangement.
then, when a button is pressed(push button) the solenoid connected to the despenser at the o/p will be 'ON' till the time set is elapsed. I need to design a circuit for doing this operation. I would take an ICM7555, which is a CMOS-555. Time constant should be set by linear 2M2 potentiometer and 6µ8 mylar cap (MKS4 for instance). Use a potentiometer with a metal enclosure and connect it to 0V. You should also use a metal enclosure for the circuit, also connected to 0V. Do not connect the switch directly to trigger input, but via a suited debouncer (RS-Nand-flip-flop, for instance). Kai |