Ah ratings battery to switch

[BinaryAssassin]

Hey all,

I have a circuit that starts with two 12v batteries 7.2AH wired in series which connect to a momentary push button switch and then to a 1.2K ohm resistor and 5mm LED (3.2 forward voltage, 20mA). My question is if the momentary switch is rated at 24v/3A will running the batteries with 7.2AH damage the momentary switch?

This small circuit is a module part of a larger one I'm trying to build.

 

[cjdelphi]

Are you simply powering the led? 24volts over kill

However 24 - 2 - 22/0.02 = 1.1k ok good but, the wattage is 0.4watts so unless you have a 1/2w resistor it's going to get hot with a 1/4watt resistor

To answer the question, unless more than 3amps flow, it will be fine..

 

[Harald Kapp]

The Ah value is irrelevantg to the question. It tells you the capacity of the battery, how much energy you can draw from the battery until it is empty.
The important value is the currrent drawn by the load.
The total battery voltage is 2*12V=24V. The voltage drop across the LED is 3.2V, therefore the voltage drop across the resistor is 24V-3.2V=20.8V. This voltage will force a current of 20.8V/1.2kΩ=17mA. This is way less than your switch tolerates.

John is right that this setup is overkill as ~0.4W are dissipated uselessly in the resistor.

 

[BinaryAssassin]

well the circuit I explained is only a small part of another one that controls another device which uses 24v @ 1A

 

[davenn]

well the circuit I explained is only a small part of another one that controls another device which uses 24v @ 1A

well that's still 2 A less than the rating of the switch you referred to

 

[BinaryAssassin]

cool. Just wanted to double check everything so I don't burn things up