how will i include the voltmeter when doing a science project trying to power a fan by a lemon?

Question

i need help!!!! {=[

Answer 1

If you do not have the high impedance volt meter use whatever you have. Considering the power demands of the fan the voltmeter's power consumption will be insignificant.

Answer 2

I don't believe you can get enough power from a lemon battery to make a motor turn. Maybe you should try to light an LED instead. Connect voltmeter in parallel to the LED or other low power device.

To get the most power from a lemon battery, you will need to use very large area plates spaced very close (but not touching) together in the lemon. The plates have to be made of different metals, like copper and aluminum. Use a very large lemon.

Answer 3

For such a low current source, I would recommend that you use a high impedance meter. A digital multimeter would fit that need for your measurement need. The meter test leads would be placed in parallel across the "battery". Red lead to the positive terminal, and the black lead to the negative terminal. That would give the voltage of your power source without loading it down. I wouldn't use a simple meter with a series resistor since this will draw more current from the battery than what it can spare to power the fan, and the meter. Use the high impedance meter that has been recommended.

Answer 4

Your lemon battery is really a single cell. Each pair of plates that you insert into a lemon will form a single cell. Connect multiple cells together in series and you will have a battery.

(Yes we call AAA, AA, C & D cells batteries but they are single cells. The common 9volt battery is a truely a multi cell battery)

The voltage created by the cell will depend upon the use of dis-similar metals such as copper and zinc and their relationship in the galvanic series.

For a cell to generate current it needs surface area of the plates. Cells in parallel (POS of one cell connected to the POS of the next, same goes for NEG poles) will generate more current at the same voltage because you are effectively increasing surface area. To increase voltage you will need to place cells in series to allow the voltages to add (connect the POS of one cell to the NEG of the next and so on).

You can demonstrate the different voltage produced by using different types of metals .

The acid in the lemon is the electrolyte of the cell. You can also experiment using different electrolytes such as salt water, vinegar, and other house hold products. The type of electrolyte used will also effect the amount of current produced.

Since your lemon battery is small you can not only measure voltage produced with a DVM, but the current produced as well. Since a small current will be produced by a lemon battery you can measure the current directly (without a load, a light fan, resistor etc in series with the meter and battery) with the DVM. (do not do this with a regular battery or cell without a load as the currents produced will be much larger)

Answer 5

A voltmeter goes across both metal terminals in the lemon.
But you'd need a low enough range to measure <1 volt.
If using the ammeter scale, it would connect in series.