Re: voltage divider or series current resistor
- From: "austingoofball" <austingoof@xxxxxxxxx>
- Date: 5 Mar 2007 19:43:50 -0800
On Mar 5, 11:59 am, NJM <guitch...@xxxxxxxxxxx> wrote:
I am just a beginner so forgive me if this question is stupid.
On a simple circuit, like 2 LEDs with a 12v supply, which would be better,
a voltage divider to lower the voltage or a series resistor to restrict
the current? Or am I completly wrong in my understanding of a voltage
divider?
Please correct me if I am wrong, but it seems the divider would actually
waste some energy because it is being sent to ground.
A little perhaps. When you put the LED into the split off of the the
divider, you're basically going to be shorting the bottom resistor to
ground. Not quite because there is a small voltage drop across the
diode, and thus a small one across the the bottom resistor. Most of
the voltage will be dropped across the top resistor, so in effect you
have a current limiting resistor with another resistor that bleeds a
little bit of current off to ground.
The voltage divider process depends on the fact that the resistance of
whatever is being driven by the divider is much greater than the
Thevenin resistance of the divider (in this case, the upper and lower
resistances in parallel). If it is, then the output Voltage of the
divider given by the Voltage Divider equation. If it isn't, then the
output voltage sags due to the voltage dropped across the upper
resistor.
.
- References:
- Prev by Date: Used DVM for SPL (Sound Level) Meter
- Next by Date: Re: voltage divider or series current resistor
- Previous by thread: Re: voltage divider or series current resistor
- Next by thread: Motion Sensor with LED's
- Index(es):
Relevant Pages
|
