Hello!
I have an old HP 11-C calculator which is powered by those button batteries. (In fact, I even have a newer model that is powered by 3V lithium cells also, but I want to deal with the older model first.)
I can see the positive and negative connectors for the series batteries (it has 3 button batteries, so I guess that is 3 x 1.5 = 4.5 volts)
My question is, can I rig up three AA batteries in series (4.5 volts also) and adjust the resistance with resistors to provide the same power level to the calculator? (Attach wires to the battery connectors on the device itself).
It seems pretty straightforward but of course I am assuming it is deceptively simple and that is not as easy as it looks? (I would probably try to make some measurements of current using a DMM with the original button batteries in series).
Mostly I am not sure how to make sure the current is not too strong, but when I think about it, if I increase resistance, the voltage will drop also.
I have an old HP 11-C calculator which is powered by those button batteries. (In fact, I even have a newer model that is powered by 3V lithium cells also, but I want to deal with the older model first.)
I can see the positive and negative connectors for the series batteries (it has 3 button batteries, so I guess that is 3 x 1.5 = 4.5 volts)
My question is, can I rig up three AA batteries in series (4.5 volts also) and adjust the resistance with resistors to provide the same power level to the calculator? (Attach wires to the battery connectors on the device itself).
It seems pretty straightforward but of course I am assuming it is deceptively simple and that is not as easy as it looks? (I would probably try to make some measurements of current using a DMM with the original button batteries in series).
Mostly I am not sure how to make sure the current is not too strong, but when I think about it, if I increase resistance, the voltage will drop also.