I'm trying to figure out whether I should make R 1 or R 2 be the variable resistor-and what value to use for the other ( fixed ) resistor.
32.
So changing the dial is changing the variable resistor, and will affect the future speed at which the capacitor charges, but will not affect how much it charged so far.
33.
:A volume control is just a variable resistor-if you have any construction skills you could buy a'potentiometer'( aka : a'variable resistor'or a'pot') and wire it up in series with your headphones.
34.
I have been considering using a car battery and a self built variable resistor from carbon rods, but as you said I'd be afraid some part of the system would smoke.
35.
:A volume control is just a variable resistor-if you have any construction skills you could buy a'potentiometer'( aka : a'variable resistor'or a'pot') and wire it up in series with your headphones.
36.
You could hook each one up in turn to a variable resistor and slowly change the voltage until the LED lights with an acceptable brightness ( or blows up ! ).
37.
I want to obtain a controlled variable voltage from a 12 volt car battery to power a full current load which can be done with a variable resistor having a center tap.
38.
In addition, the load resistance is often not known and therefore simply placing a variable resistor in series with the load could have a negligible effect or an excessive effect, depending on the load.
39.
Another gotcha is that over most of the range of the variable resistor ( > 10 ohm ), your resolution is going to be far worse than if you use a larger fixed resistor.
40.
A voltage source and a series connected variable resistor may be regarded as a direct current signal source for a low resistance load such as the control coil of a saturable reactor which amplifies the signal.
