12V Leisure Battery status using 2x LM3914s

[garynobles]

Also im trying to figure out which diode to get, there are so many to choose from!

Hows this one? https://uk.farnell.com/nte-electron...rch=Featured New Products&MER=i-9b10-00002068

 

[alec_t]

Sorry about the typo. Only 4 diodes needed. 1N4148 or other signal diode would be better than 1N4004 (which is a power diode).
Ignore the suggested FET (that's what the Spice simulator was using); use any convenient 3-terminal N-MOSFET with adequate voltage/current ratings.

 

[garynobles]

Well last post was in July last year! But I'm back again, I semi gave up on this but now for another go.
I have the circuit board and components all soldered in place, but it doesn't work!
For some reason I have the following values from the LM3194:

IC1

pin 1: 11.65v
pin 2: 0
pin 3: 12.07v
pin 4: 0
pin 5: 0.66v
pin 6: 0
pin 7: 0
pin 8: 0
pin 9: 12.07

IC2 is similar
so the sig (pin 5) seems far too low and I don't know why the Rhi, Ref and Adj are zero (pins 6-8)
As for the trimmers, they are all at zero as nothing is coming from pins 4,6,7,8
The pnp transistors and LEDs work when I touch the base with my voltmeter as it acts as a sink

the mosfet and capactitor have readings of only 0.66v

Any ideas?

Gary

 

[chemelec]

What is the Schematic of this?
Is this built on a Breadboard, Stripboard or a Circuit Board?

 

[garynobles]

Hi chemelec, the schmatic is on the previous page, https://www.electro-tech-online.com/attachments/circuit10-jpg.74922/

I've got the PCB made as my breadboard wasn't big enough for full test.
It just doesn't seem to be pulling the voltage as it should (not sinking through the LM3194)

Thanks for any help

Gary

 

[chemelec]

Your Circuit is a Bit Confusing with all those "Driver Transistors" and being so Spread Out.
Why do you need them?
The LM317 can easily drive an LED Directly.

What about just using one of My Circuit?
It can easily Monitor your Battery Voltage. from 0 to 15 volts
http://chemelec.com/Projects/Volt-Meter-2/VoltMeter-2.htm

Or This Expanded Voltmeter Circuit can read from 10.25 to 15 Volts
http://chemelec.com/Projects/Volt-Meter-1/V-Meter.htm

Not sure Where you Live, but possibly we could talk on the phone.

 

[garynobles]

Thanks for the reply,
I can't use the IC directly with the LED Module I'm using as it has a common ground, the IC is a sink.
Therefore I need the pnps to, in effect, reverse the sink effect.
Sorry if its a bit spread out but I was trying to keep it clear as the pnps make it a bit busy.
I'm just trying to understand why the various pins register zero volts, with a 12v input surely some should be on?

Here is a simpler schamtic from last year https://www.electro-tech-online.com/attachments/16ledvoltmeterbardotslowed-gif.74907/
You seemed to be able to get it to work last time.

I wanted a personalised circuit as I want a specific range from my 12v leisure battery, hence the use of the ref and adj pins etc.

 

[chemelec]

OK on the Transistors.
Not sure Why no correct Voltage Readings.

So why not build My Circuit using My PCB Design, than make a Second board with the Transistors on it and join them with interconnecting wires.
I Know Positively both above circuits and Pcb's do work.