I have been learning about voltage dividers most of it has been theory based and lots of maths , I was thinking it would be nice to do something more practical rather than just theory work, so if anyone can help me with a basic schematic using a battery power and just two resistors but more importantly i want to put a voltage load on one of the resistors so i can do more testing, I haven't had much practical work but i have a breadboard and various components, i was thinking about using an led but i am not sure it work well for a voltage load .

 

hi d7,
This may help.
E
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/voldiv.html

 

What do you want the LED to show from the resistive divider output?
What is a "voltage load"?
In general an LED does not seem to be an appropriate load for that.

 

Do you know what happens when you put a load on a voltage divider?

Bob

 

I have been learning about voltage dividers most of it has been theory based and lots of maths

It's just simple arithmetic.

if anyone can help me with a basic schematic using a battery power and just two resistors but more importantly i want to put a voltage load on one of the resistors so i can do more testing

Using a voltage divider as a power source is almost always the wrong thing to do. The rule of thumb for voltage dividers is that the divider current should be 10 times the load current. If you do the calculations, you'll see that going that route is very inefficient because the voltage divider will dissipate more power than the load.

If you want an example, you need to specify the output voltage you want and what the load current will be.

Also, we don't qualify loads with voltage. It's just a load.

i was thinking about using an led but i am not sure it work well for a voltage load .

LEDs should always have a current limiting resistor.

Also note that since LED is an acronym for light emitting diode, it should be written with all caps. It's also pronounced L-E-D, not led.

 

Voltage dividers are used to provide reference voltages to a high impedance input and should never used to power a load. (especially a variable load)

To make a divider to power a load the load itself becomes one half of the divider and forms a simple series circuit.

I blame the internet and lack of basic electronic education for this misconception about voltage dividers.

 

Voltage dividers are used to provide reference voltages to a high impedance input and should never used to power a load. (especially a variable load)

To make a divider to power a load the load itself becomes one half of the divider and forms a simple series circuit.

I blame the internet and lack of basic electronic education for this misconception about voltage dividers.

Very true, it's a rooky mistake I have made myself in the past.

One simple modification that can make that work with small loads is a simple opamp in the "voltage follower" configuration with a voltage divider as reference. And of course since the input of an opamp is at such a high impedance, big resistor values can be used for the divider in order to save on power. Definitely not for powering motors or what have you, but for low power applications at least it can serve as a supremely simple voltage regulator of sorts.

 

You might consider a small 'buck converter' able to handle the load you intend. Easy enough to build or cheap to buy.
Some are adjustable from the source voltage to zero volts.
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