# Controlling the current

#### sobow6

Joined Jan 8, 2016
2
This may be a dumb question, but I am self teaching myself electronics to be able to make cool gadgets and mods for my motorcycle.

I am struggling with amperage. How to control it and how to protect my circuits from too much of it. I attempted to reduce the voltage of my battery (12V) to about 6V with a resistor, which worked! However, when I plugged the circuit into my Motorcycle battery it burned the resistor up pretty quickly.. This did not happen on the bench with a series of AA batteries equalling 12V.. I am very confused.

#### #12

Joined Nov 30, 2010
18,216
The best way to protect your devices from excess current is to use devices rated for a 12 volt motorcycle system.
The battery does not force several hundred amps through each device connected to it. It provides 12 volts. The devices decide how much current will flow because of their internal resistance.

#### crutschow

Joined Mar 14, 2008
25,989
What do you need the 6V for?

#### Alec_t

Joined Sep 17, 2013
11,796
I am self teaching myself electronics
Excellent. It's a rewarding hobby. If you haven't already done so, get yourself familiar with the basics of voltage, current, resistance and Ohm's Law, which links them.

#### AnalogKid

Joined Aug 1, 2013
8,805
You don't give any circuit details, so real answers are not possible, but in general...

The electrical system in a motorcycle is capable of supplying over 100 watts, while a AA battery can supply only a one or two watts. The reason the resistor did not burn up on the bench is that the batteries could not supply enough power to burn it up. The way electricity works, you provide a voltage to a circuit, and the circuit draws the current it needs, up to the point where the power source cannot provide it. This is what saved the resistor on the bench, the batteries acted as a current limiter. The electrical system on a bike also has a limit, but it is much higher.

ak