Hi All-
I am working on a project and 555 is one of the part. The idea is 24vdc is powering the circuit. It has a switch which need to be monitored. The relay is bistable relay to remember the previous state. So I have a 555 based circuit which will be powered up by 5v derived from 24v. E output of switch going to load/relay is sensed and fed to 555 monostable multivibrator trigger. Whenever the switch is off it will trigger the 555 enabling transistor to switch the state to off position.
This works fine as per required. But when I power cycle the 555 timer is triggered (internally)triggering relay to switch off. To ensure the power up isn't triggering the 555, I also tied trigger pin to 5v and also to 24v.
Are there any pointers to address this problem. The schematic is added.
I am working on a project and 555 is one of the part. The idea is 24vdc is powering the circuit. It has a switch which need to be monitored. The relay is bistable relay to remember the previous state. So I have a 555 based circuit which will be powered up by 5v derived from 24v. E output of switch going to load/relay is sensed and fed to 555 monostable multivibrator trigger. Whenever the switch is off it will trigger the 555 enabling transistor to switch the state to off position.
This works fine as per required. But when I power cycle the 555 timer is triggered (internally)triggering relay to switch off. To ensure the power up isn't triggering the 555, I also tied trigger pin to 5v and also to 24v.
Are there any pointers to address this problem. The schematic is added.