I have a circuit that runs continuously at 5V and 150mA that I would like to turn off and turn on again once every day.

I was thinking I could power it through the normally closed contacts of a relay and, once a day, briefly actuate the coil of the relay to cut power and re-establish it moments after.

For that, I have a micro controller with a timer, working with 4xAA (6V), that wakes up once a day and switches ON an n-channel mosfet, which would energize the coil and switch its contacts.

Looking at the attached picture, would this circuit be adequate? Would I need the 100 ohm resistor in series with the coil to limit the current going through it even further?

https://ampul.eu/en/relays-magnetic-contacts/2686-relay-srd-06vdc-sl-c-6v-dc-250v-ac-10a

 

With a coil resistance of 100 ohms an additional 100 ohms would be way too much.

I doubt that relay will pull in at 3 volts.

Also, you might want to look at a different kind of relay to switch 150mA. (small signal type)

 

Unless you specifically need isolation between the two circuits I’m wondering why you need a relay? Could your circuit include a transistor normally powered on such that the processor turns it off once every 24 hours?

 

OR -

Walmart lamp timer >> 5 V USB wall wart >> device.

ON - 23 hours, 59 minutes

OFF - 1 minute

Repeat.

ak

 

How accurate does the timing need to be??? Both time of the event and the length of the event.???