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Voltage Dividers

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CrackBadger

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I just got into voltage dividers but I don't understand what they mean by it.

**broken link removed**

What exactly is the point of this circuit here? Lets say theres an initial 10V from the power source. At first I have R1 (potentiometer) set so it cuts the voltage down to 2V. Lets say R2 is an LED. Would I basically use R1 as a dial to make the LED brighter or darker by lowering and raising the resistance?

Or lets say I had a red LED attached to the circuit before R1. That would mean the red light would be constantly lit by the 10V but at the same time I would vary the brightness of the green light (R2).

Is that the idea of voltage dividers? I'm reading the Art of electronics and its giving good examples but they're explaining the concept with things I haven't learned yet like signal in, signal out etc.

What is a signal? AC voltage? Also they mention a load resistor. Whats that? And finally what is a reference voltage?
 
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Lets say R2 is an LED. Would I basically use R1 as a dial to make the LED brighter or darker by lowering and raising the resistance?
Yes, that would work as long as you didn't turn R1 down to too low of a resistance and burn the LED out. Generic LEDs will burn out if you pass more than apx 30ma though them.

A better example would be:
R1 = 18:eek:hm:
R2 = 2:eek:hm:
Vin = 10V
So.... total resistance of the circuit is 20:eek:hm:. So 0.5Amps will flow ( 10V / (18+2:eek:hm:)) = 0.5A
0.5 amps accross 2:eek:hm: equals a 1V drop ( 0.5A * 2:eek:hm: = 1V) Google for "ohms law" if you don't understand the formulas or where they come from.
 
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You can't use an LED in a variable voltage divider because an LED is a diode with a fairly constant voltage across it. An LED is not a resistor. An LED gets brighter with more current, while its voltage stays almost the same.
 
Can you give me some examples of voltage dividers? What advantages are there of having a different voltage across one component than the voltage across another one?
 
CrackBadger said:
Can you give me some examples of voltage dividers?
You posted a perfect example in your original question. If you want a practical example, it would be a voltage divider used to bias a transistor amplifier. While the circuit shown is far from ideal, there is some nice java script to play with so you can see what different divider ratios would do to a circuit:
**broken link removed**
 
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