When we use voltmeter without resistance,(parallel connection) I thought it might have potential difference between two points, because of this equation V=Ed I thought There should be small difference 'd' between two points. So i connected what i said and I was embarrased to see "0" on my voltmeter. So i wonder why this happen although V=Ed says there might be potential difference between two points. I'm not a English user, so I'm sorry for my bad English. But I hope someone could help me get out of this chaos.
Figure 1. Battery equevalent Circuit with load resistor.
- Every battery has some internal resistance. This is shown in Figure 1.
- You have created a voltage divider by placing your "resistor" across the battery terminals.
- With the values I have shown there will be about 1% of battery voltage on your test wire. For a 1.5 V cell that will be 15 mV.
- If you measure at both ends of that wire you might see that much voltage - but it depends on the resistance of the wire.
If you can find a long length of resistance wire and repeat your experiment you won't be so embarrassed. If you don't have suitable wire then make a chain of resistors and measure various points along it.
You might read about battery ESR being some value but remember that is only for a specific range of battery currents. Batteries are highly non linear devices with highly time dependent parameters especially at higher discharge rates.
I have done a lot of work with batteries and "ESR" can be very different with state of charge, temperature and load current.