When I use a 9V battery and put the ampere meter on to see the voltage of the battery, it reads 9.50V which is more than that of the battery. How could this happen. I am calculating the effeciency of various batteries. Any tips, ideas and the answer to the question please.
THank You
2007-03-12 11:54:51 · 3 answers · asked by armenharoutunian 2 in Science & Mathematics ➔ Engineering
Voltage is measured with a voltmeter, not an ammeter (your "ampere meter.")
The reading you saw is quite normal. The open-circuit (unloaded ) voltage of a new battery will always be a little higher than the normal operating (loaded) voltage.
If you measure the voltage again with a load, a bulb say, you will see that it is slighty lower than your original reading.
2007-03-12 12:09:08 · answer #1 · answered by dmb06851 7 · 0⤊ 0⤋
Well, for starters it is very weird that you're using an ampere meter to measure volts, but assuming that the 9.50V reading is actually the voltage, here's what could be the case:
Though unlikely, it could be that you have faulty equipment, meaning either your battery is weird, or your meter is inaccurate/not calibrated.
What's probably more likely is that the label on a battery that says what voltage it is, is by no means correct. The voltage is actually in a broad range, declining as the battery is used up. The value given on your battery, 9V, is the battery power expected when in a proper circuit, with a current running. Due to the battery's own inperfections, it has an internal resistance that causes the voltage to drop as the current increases. When hooked up to a volt meter, there is no current, so no loss, which could account for the 9.50V. While it is hooked up to a proper circuit the voltage of the battery is lower, probably closer to the value that it says on the batt, 9 V.
2007-03-12 19:12:47 · answer #2 · answered by Martin vM 2 · 0⤊ 0⤋
an ampere meter measures the current not the voltage
or
the current is short circuiting
2007-03-12 19:05:09 · answer #3 · answered by Erica H 2 · 0⤊ 0⤋