rfranzk
Member
Hello All,
I am in need of a circuit to drive a couple of 12 volt dc solenoids 7 watt at alternating on off cycles of approximately 30 seconds to one minute. I was thinking of using a single 555 and driving one npn transistor and one pnp transistor from a 555 output. I don't know if that is feasible or even possible. The circuit needs to be fairly robust and able to drive these two solenoids for 1 to 2 hours continuously. So when one solenoid is on the other is off and then switching states at 30 second to 1 minute intervals.
The solenoids are rated at 7 watts and I will be powering the circuit with a regulated 12 volt 10 amp supply. I measured the resistance of the solenoid coil at 22 ohms and that gives current of 12/22 =.545 amps. I would like to use bipolars or mosfets capable of at least one amp to provide a little margin. The timing is not critical and some adjustment would be handy and a 50% duty cycle is just right.
I can build almost anything but design is out of my league at this point in time. Something I am gradually learning.
Any help would be appreciated.
Thanks. rfranzk
I am in need of a circuit to drive a couple of 12 volt dc solenoids 7 watt at alternating on off cycles of approximately 30 seconds to one minute. I was thinking of using a single 555 and driving one npn transistor and one pnp transistor from a 555 output. I don't know if that is feasible or even possible. The circuit needs to be fairly robust and able to drive these two solenoids for 1 to 2 hours continuously. So when one solenoid is on the other is off and then switching states at 30 second to 1 minute intervals.
The solenoids are rated at 7 watts and I will be powering the circuit with a regulated 12 volt 10 amp supply. I measured the resistance of the solenoid coil at 22 ohms and that gives current of 12/22 =.545 amps. I would like to use bipolars or mosfets capable of at least one amp to provide a little margin. The timing is not critical and some adjustment would be handy and a 50% duty cycle is just right.
I can build almost anything but design is out of my league at this point in time. Something I am gradually learning.
Any help would be appreciated.
Thanks. rfranzk