# What happens if an electronic device only uses 20 mA, but the power supply gives 700 mA? [duplicate]

I’ve recently been wondering if my IC would get fried if I have a 700 mA power supply? Since the IC only needs 20 mA.

Also I don’t understand resistance in Ohm’s law since I didn’t put any resistor. How can there automatically be resistance?

• It depends if it is a constant current supply or constant voltage supply. We don't know what you have. Add as much info you can about your power supply and your IC. Jul 4, 2023 at 19:17
• you will need to look also to the power that can be supplied and the power your IC is consuming. Every IC consuming can be modeled as a resistor that consumes power. Jul 4, 2023 at 19:18
• Your power supply can produce 700mA but it does not have to!. If you unplug the load it produces 0mA. The load takes 20mA of the available 700mA. It is ordering a pie and only eating one piece. You don't have to eat the entire pie.
– user338146
Jul 4, 2023 at 19:27
• @ronsimpson Not true if it is a constant current supply. It will try to push 700mA no matter what through the load until voltage has reached maximum. Jul 4, 2023 at 19:33
• @brhans That's some phone charger! Jul 4, 2023 at 21:41