Hello, not a homework question for me, but I figure this is a good enough forum to ask.
I'm a bit confused by a voltage divider circuit I was working on, perhaps someone can shed some light on the subject for me?
I have a 5 volt source (through a 7805) and I want to provide power to a pager motor that is rated at 95ma @ 3 volts.
I breadboarded a voltage divider using two 1k resistors (i have a ton of 1k resistors). From my calculation the 2 1k resistors will cut the voltage in half.
I measured the voltage drop across each resistor at about 2.45 volts, which is fine as the voltage from the regulator is around 4.9 volts or there abouts.
Here's the rub. I hooked the motor up incorrectly at first, in series with the resistors (rather than in parallel with the second resistor). The motor didn't spin at all. And this is the crux; I cannot figure out why!
I know i hooked it up wrong, but I cannot figure out why the motor doesn't move at all, unless I'm not giving it enough juice to start moving? I hooked up a spare LED in series and it lit up, not strongly but not so dim as I had trouble seeing it.
The other question I have about voltage dividers, is: How do I know what the optimal resistor value is for my circuit? Why not use a 10k resistor instead of a 1k resistor? I know about using the 10% rule for accounting for a load, but I just read that last night (after I put everything away) so perhaps my 1k resistors are the wrong choice here.
Cheers and Thanks!
Shane
I'm a bit confused by a voltage divider circuit I was working on, perhaps someone can shed some light on the subject for me?
I have a 5 volt source (through a 7805) and I want to provide power to a pager motor that is rated at 95ma @ 3 volts.
I breadboarded a voltage divider using two 1k resistors (i have a ton of 1k resistors). From my calculation the 2 1k resistors will cut the voltage in half.
I measured the voltage drop across each resistor at about 2.45 volts, which is fine as the voltage from the regulator is around 4.9 volts or there abouts.
Here's the rub. I hooked the motor up incorrectly at first, in series with the resistors (rather than in parallel with the second resistor). The motor didn't spin at all. And this is the crux; I cannot figure out why!
I know i hooked it up wrong, but I cannot figure out why the motor doesn't move at all, unless I'm not giving it enough juice to start moving? I hooked up a spare LED in series and it lit up, not strongly but not so dim as I had trouble seeing it.
The other question I have about voltage dividers, is: How do I know what the optimal resistor value is for my circuit? Why not use a 10k resistor instead of a 1k resistor? I know about using the 10% rule for accounting for a load, but I just read that last night (after I put everything away) so perhaps my 1k resistors are the wrong choice here.
Cheers and Thanks!
Shane