SCALING OF VOLTAGE

[paridhi jain]

how to scale the 9V to 660mV.

 

[JimB]

A simple voltage divider using two resistors, is an easy way to do it.

JimB

 

[paridhi jain]

yes, i m using voltage divider my resistor burn.

 

[paridhi jain]

r2/r1 = 12/1
I take the output form r2

 

[Ian Rogers]

Use a 1k preset for R2 and a 33 ohm for R1

 

[JimB]

how to scale the 9V to 660mV.

yes, i m using voltage divider my resistor burn.

r2/r1 = 12/1
I take the output form r2

Instead of these simple one line statements, why don't you tell us what you are trying to do?

Where does the 9volts come from?
Where does the 660mV go to?
Your resistors burned? what value (ohms) were your resistors?

The more information you give to us, the better we can help you.

JimB

 

[cowboybob]

yes, i m using voltage divider my resistor burn.

In addition to the questions JimB posted above, it would also be useful to know the current (I) requirements of your circuit and the power rating(s) of the resistors being used.

 

[audioguru]

Your power supply is 9V and your voltage divider produces 660mV. Then if the lower resistor is a 1/4W one it will burn if its current is 0.25W/0.66V= 379mA or more and if its value is 0.66V/379mA= 1.74 ohms or less.
The upper resistor will have 9V - 0.66V= 8.34V across it and its heating is 8.34V x 379mA= 3.16W. Its value is 8.34V/379mA= 22 ohms.

Why are your resistor values so low causing the current and heating to be so high?? Use a 1.74k resistor for the lower one and a 22k resistor for the upper one and they will stay cold.

 

[ronsimpson]

how to scale the 9V to 660mV.

I don't why you want to get 0.660 volts.
If you need 0.66 volts to run a motor then that is a very different thing.
If you need 0.66 volts to drive a small meter then that is another thing.

More information please.

 

[audioguru]

Is 0.66V the base-emitter voltage of your transistor or forward voltage of your diode?

 

[paridhi jain]

i want to r

I don't why you want to get 0.660 volts.
If you need 0.66 volts to run a motor then that is a very different thing.
If you need 0.66 volts to drive a small meter then that is another thing.
i want to run small meter

 

[spec]

i want to r[un a small meter]

We need to know more about the meter: is it an ammeter (current drive) or is it a voltmeter- multimeter perhaps- tell all