Battery indicator circuit

[ericgibbs]

Well i have multisim but can install LTSpice, last time I did though it was not exactly user friendly, but why won't it work in multisim then ?

this is the result you will get, either low ON or full ON , not both.

Are you trying to get both ON at the same time for mid range voltages.???

 

[Thunderchild]

this is the result you will get, either low ON or full ON , not both.

Are you trying to get both ON at the same time for mid range voltages.???

yes the idea is that one come on UNDER the higher voltage and other other OVER the lower voltage, this way the gap between the two voltages will see both on and so the orange/yellow light in a tri-colour lead

that graph you have looks like its exactly as it should be

 

[ericgibbs]

yes the idea is that one come on UNDER the higher voltage and other other OVER the lower voltage, this way the gap between the two voltages will see both on and so the orange/yellow light in a tri-colour lead

that graph you have looks like its exactly as it should be

The graph shows both OFF, [ the LM339 outputs are HIGH] between the Low and High.
Thats the point Ive been trying to put across..

I'll post cct tomorrow if thats OK.? to do what you are expecting.

 

[Thunderchild]

The graph shows both OFF, [ the LM339 outputs are HIGH] between the Low and High.
Thats the point Ive been trying to put across..

I'll post cct tomorrow if thats OK.? to do what you are expecting.

oh yes i see of course its reversed logic, well all I need to do is revers the comparator inputs ?

 

[ericgibbs]

oh yes i see of course its reversed logic, well all I need to do is revers the comparator inputs ?

hi TC,

The way I would do it is,

Make the Low led come ON at say less than 12.5V [ and stay ON while less than]

Make the Full come ON when greater that say 12V [ and stay ON while greater]

This way both leds will be ON between say 12V and 12.5V

You can choose the 12V and 12.5V settings to suit you project.

OK,?

 

[ericgibbs]

hi TC,
This what I had in mind.

 

[Thunderchild]

hi TC,

The way I would do it is,

Make the Low led come ON at say less than 12.5V [ and stay ON while less than]

Make the Full come ON when greater that say 12V [ and stay ON while greater]

This way both leds will be ON between say 12V and 12.5V

You can choose the 12V and 12.5V settings to suit you project.

OK,?

yes thats exactly what the intention was, I've worked on the diagram again and got it right this time I had both comparator inputs switched. the reason why it was totally dead in multisim was because the led resistors were too high

 

[ericgibbs]

yes thats exactly what the intention was, I've worked on the diagram again and got it right this time I had both comparator inputs switched. the reason why it was totally dead in multisim was because the led resistors were too high

OK,
I would say that in a practical circuit the 100R driving the 5V zener is to low a value.

Iz= (13.8-5)/100 = 88mA....also its an extra current load for the battery

 

[Thunderchild]

OK,
I would say that in a practical circuit the 100R driving the 5V zener is to low a value.

Iz= (13.8-5)/100 = 88mA....also its an extra current load for the battery

yes I know i did it just for the simulation to make sure it did work I know that in real life I'd be frying zeners, I think 500ish is more like what i want.