Hello
How to make battery level indicator
9v battery show 3v 6v at two led with voltage divider

 

Hello
How to make battery level indicator
9v battery show 3v 6v at two led with voltage divider

Hi, what exactly do you want to do? Your question is vague.

 

Hello
I want to make 9v battery level indicator when i change voltage it should 3v and 6v and 9v led

 

Hello
I want to make 9v battery level indicator when i change voltage it should 3v and 6v and 9v led

I'm having trouble understanding your English but that is ok. I think you want to make a battery tester for 9V batteries? If so it would be something like this?

1 LED on = 3V
2 LED on = 6V
3 LED on = 9V

If so, there are many ways to make a circuit, what is your level of electronics knowledge?

 

Hello
3v led 1
6v led 2
9v led 3

 

I think that he wants to make a voltage indicator that lights one LED for each 3 V of voltage, So 2 LEDs would indicate that the voltage is at least 6 V but less than 9 V.

@mumbai: Is that close? Please tweak the description as needed.

Why are you doing this? Is it a school assignment?

What is this circuit being powered by? The battery that you are indicating the voltage for?

How accurate to the thresholds need to be?

Do the LEDs need a sharp turn on?

 

Here is a circuit I made with LTspice. The graph is showing a simulation where the supply voltage increases from 0 to 12V. The first LED will turn on at about 3V depending on the colour you choose. The second will turn on at 6V and the third at 9V. The circuit costs a few dollars to make and I can test the circuit if you want.

 

Hello
Yes i want to make 3v led and 6v and 9v led when i make voltage down led should off

 

Hello
Can you understand

 

Hello
Can you understand

Whomever came up with that didn't think it through very carefully.

 

Whomever came up with that didn't think it through very carefully.

What about mine? I appreciate the honest critique. I think it's too complex for him but was fun to make. I think we wants to build the kind that adds the forward voltages of the LEDS. In that case, he will probably be disappointed.

 

If the battery is a PP3 and its voltage is much below 8V then the battery is as good as dead for some applications. Monitoring the 6-9V range might be better.

 

Having an LED that lights for 9V means you are wasting an LED since it will almost never be lit—if ever. The top indicator should be less than 9V to be useful.

 

I agree that most of your battery voltages show a dead battery that does not produce enough energy to do its job but it might dimly light an LED. Then the dim LED will kill the remaining power from the battery.

 

Hello
How to make battery

 

Hello
How to make battery

We buy a battery, we do not make a battery.

 

Might make a good science fair project.

 

Small comparator IC, you can find them 4 on one IC. Then just tune the thresholds accordingly. Many of them won't even need a drive transistor for LED.