what part or schematic for dual polarity


i have one electromagnet that works under 110v dc .
i am building a project that an arduino can detect when my electromagnet is powered on .

i have build this electronic schematic that works

Are any other methods (or any electronic part) that i could use to detect when i will get 110v dc in my input but without be necessary the polarity of the 110v dc as it is in my schematic .

thanks in advance

Yes. A bridge rectifier may be the simplest way, but you could use an additional zener diode plus an optocoupler that accepts AC (by using two antiparallel photoemitters, for example). There are other ways as well.

Seems excessive to me! What's wrong with an 11k resistor from the 110V supply to the TLP621 to give 10mA through the LED?

It will need to be a 2W resistor.

By the way, these methods tell you when the 110 VDC is connected and on. You would need something else to tell you when current is flowing through the electromagnet.

Thanks both for the guidance !!!! :slight_smile:

vaj4088 a simple bridge rectifier will be the best option... thanks for the help... some times you can forget the most obvious solution .

i don't want to check if my electromagnet is working.. just to check when the relay gives the voltage

recently i discover a nice cheap module to check the current with Arduino ( ACS758LCB-050B/100B-PFF-T ACS758LCB Current Sensor IC Current Module)

so later on if i want to check if my electromagnet works , i can add this module to my project

thanks again both for the help

How about a hall effect sensor to detect when the magnetic field is on or off. Cheap and very compact, interfaces directly with a digital or analog input and very low power.