[SOLVED] Making Led only light at 10v

[Shaam123]

Hello,

I have designed a 12v voltage regulator on a breadboard. I can adjust the voltage using a potentiometer. I want to add a led which lights up only when the voltage is 10v. Below that, the led is off. I want to use the led as an indicator that the voltage is equal or more than 10v.

I have attached a schematic of the voltage regulator I have used.

 

[E-design]

Use LM431 on the output to switch and drive an LED.

 

[Externet]

Would a 10V Zener diode in series to the LED work ?

 

[BradtheRad]

Would a 10V Zener diode in series to the LED work ?

The led has its own turn-on threshold, a few volts probably. Therefore the zener should be 6-7 V. You'll need to experiment with different combinations.

If you want convenience in adjusting turn-on threshold, the TL431 (as I'm pretty sure post #2 intends) is an adjustable zener.

Be sure to add safety resistors where needed.

 

[FlapJack]

You need to use an op amp and build a comparator circuit.

http://www.electronics-tutorials.ws/opamp/op-amp-comparator.html

- - - Updated - - -

The LM431/TL431 is the simplest comparator circuit there is.

http://www.reuk.co.uk/TL431-Battery-Voltage-Monitor.htm

 

[Shaam123]

Would a 10V Zener diode in series to the LED work ?

Tried with a zener diode of 6.2 V and it worked.
Thanks a lot