I have a 12v adapter which has a rating of 1.5A. 1.5A is a large current. I've used the adapter to power a microcontroller board. The microcontroller board has an lm317 linear voltage regulator to step down the output to 5v but since the microcontroller uses only a few milliamps of current.. How does it handle the 1.5A of current from the adapter? Wouldn't the controller blowup?
Asked
Active
Viewed 56 times
1 Answers
-1
You need to understand the basics of Ohm's Law. I=V/R. I is the current, V is the Volts and R is the Resistance.
The resistance R is the "load". The load is what you are exposing to the voltage so to speak. Connect some load to a voltage and some current will flow, determined by the load, R. So the current which flows is the current which is drawn by the load. A source cannot "force" current through a load which it does not want.
The PSU's 1.5A is a rating. It specifies the maximum current which a load can draw, in this case 1.5A. It does not "push" 1.5A through the load because it has no capability to do so. The current which flows is entirely dependent on the resistance (and the voltage).
Ian Bland
- 2,649
- 1
- 14
- 18