what type of resister eg (10k,800ohm) would you need to change 4vdc to around 1.5 or 2???
2007-02-22 23:36:23 · 3 answers · asked by Mutley! 5 in Science & Mathematics ➔ Physics
As the others stated, you are missing some info (current). You will need to balance this equation:
Voltage = Resistance x Current
or
Volts = Ohms x Amps
If you eleminate the current by assuming it is the same in both circuits, then you have
E1/R1 = E2/R2
a quick substitution shows that
4v/10000ohms*800ohms=3.2 volts. Since 3.2 volts is not one of your options, then the current must change in order to get 1.5 or 2 and therefore you must know what the current is to determin the proper resistance.
Go back and look at the problem again and find out what the current is supposed to be.
2007-02-22 23:55:52 · answer #1 · answered by sparc77 7 · 0⤊ 0⤋
The above answer is correct.
Lets say you wanted 1.8V at 20mA
R=(4 - 1.8) / 20mA = 110 ohms
2007-02-23 07:45:39 · answer #2 · answered by Roy E 4 · 1⤊ 1⤋
you can't do this untill you know what the load is.
if you have an open circuit, you'll still have the original voltage.
2007-02-23 07:41:43 · answer #3 · answered by a1tommyL 5 · 0⤊ 0⤋