Power Push Switch and Voltage Drop?

Thread Starter

DJ_AA

Joined Aug 6, 2021
157
Hi

Is it normal that a push switch on a PCB can cause a voltage drop on a battery?

I would like to place a switch between a battery and a circuit.
 

ericgibbs

Joined Jan 29, 2010
15,976
hi DJ,
A switch with contacts rated to carry the current required by the circuit may create a very small drop in the supply to the circuit.
E
 

MisterBill2

Joined Jan 23, 2018
12,685
Hi

Is it normal that a push switch on a PCB can cause a voltage drop on a battery?

I would like to place a switch between a battery and a circuit.
Connecting an current consuming load to a battery will cause some voltage drop, which may be measurable but not enough to matter. That is because switches and wires, all exhibit a bit of resistance. The one exception is some simulators, where connections have no resistance.
 

Thread Starter

DJ_AA

Joined Aug 6, 2021
157
Thanks

Previously I had a switch and wire between the battery and PCB. So I guess that was as adding additional voltage drop.
 

dl324

Joined Mar 30, 2015
14,897
Is it normal that a push switch on a PCB can cause a voltage drop on a battery?
It would be helpful if you provided more information. Switch type, current involved, and voltage drop tolerance.

These switches have a contact resistance of less than 0.01 ohms (typical).
c&kMiniatureToggleSwitchSpecs.jpg
 

MisterBill2

Joined Jan 23, 2018
12,685
Mostly the voltage drop of one of those switches operated within it's ratings is so small that it takes a sensitive meter to measure it. That is to say that the voltage drop may be about 0.003 volts, (3 millivolts). The result is that it does not matter for normal applications. If the switch has been damaged or used far beyond it's ratings the drop may be a bit more.
 
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