smoothing out voltage spikes and dips?

[budm]

Re: smoothing out voltage spikes and dips?

Start a new thread. And hopefully we can finalize this thread when you get it running.

[scampo77]

Re: smoothing out voltage spikes and dips?

i dont know what has gone wrong but i have spent around 6 hours trying to understand why my prototype is not working and i dont even know how to describe the symptoms. i had to make a youtube video. if i disconnect the pin 9 voltage it works by just using one bulb at a time. if i try to use it like i want to then it does like what is shown in the video. it was working beautifully and i dont know what has changed. i have even pulled everytthing off of the board and stuck it to a new breadboard. i have changed all the components including the LEDs and the IC

meausements between pins.....

ohms

2-4. 0 ohm
2-3 80 ohm
2-5 0-90 ohm
3-9 0 ohm
7-8 1200
6-7 0
7-2 1700

power

3 10v
2 0v
4 0v
5 0-3v
6 5.8
8 5.8
9 10v

i think my problem is ref high on pin 6 and 7 i need to be around 400 ohms on R3 to get the desired 3v. but when i do it still doesnt change the effect im getting on the bar graph.

http://www.youtube.com/watch?v=UM_Az...ature=youtu.be

[budm]

Re: smoothing out voltage spikes and dips?

Which diagram are you using? Rev 2 is the correct one. The way it is acting in the video, it looks like the LED connections are crossed some where. It has to be your wirng or your bread board has internal short some where.

[scampo77]

Re: smoothing out voltage spikes and dips?

yes rev2, and it was working i dont know what went wrong.

i am using rev2 but with the damping circuit

[scampo77]

Re: smoothing out voltage spikes and dips?

if my resistors i used for the prototype are too small (1/8th watt) will this cause these symptoms. it seems that when i only have one or two bulbs on it goes crazy. my logic was that when the circuit is turning a lot of current into heat it seems i am having problems.

is this possible?

[budm]

Re: smoothing out voltage spikes and dips?

Only the 200 Ohms will have to be 1/2W or more.

[scampo77]

Re: smoothing out voltage spikes and dips?

do you have any idea to help me diagnose this? ben7 seems to have disappeard

i have stopped the PCB design until i figure out what is wrong with this.

[budm]

Re: smoothing out voltage spikes and dips?

I don't know since you were able to build the prototype and it works, so I would say, start from scratch again and verify all the connections one by one WITHOUT the damping ciruits for now.

[scampo77]

Re: smoothing out voltage spikes and dips?

I don't know what I have done but I completely disassembeled and reassembeled and it is working again. Atleast now I can go back to the pcb designi will post the image before I build it.

One more question I have is. Is it possible to add a dimmer to the LEDs? I think I did it with one of my originaldesigns by accident.

[scampo77]

Re: smoothing out voltage spikes and dips?

If it is too difficult to use a dimmer to dim the bulbs. would it be possible to disengauge pin 9 when i turn on the head lights? using something like a TO-92 case transistor?

also I plan to drive 20 bulbs off of 2 LM3914. do I need a second PSU? 2x LM317?

[scampo77]

Re: smoothing out voltage spikes and dips?

Everything is looking very good here is my work so far on the printed circuit board. i used express pcb because it was free and seemed very basic.

the only thing i cant figure out is how to invert one side so i can transfer the image to the circuitboard.

[scampo77]

Re: smoothing out voltage spikes and dips?

so my gauge went into commercial service and it seems to be standing up just fine. I am hoping someone is still alive on this thread because I am back And I could sure use a hand with a tune up on my level gauge.

it is for applying voltage to pin 9. with voltage applied to this pin its a bar graph. its great for bright days. with no voltage applied its just a dot gauge. great for at night.

I hooked it up to a relay but I guess after this many clicks back and forth it has died. I am hoping to come up with a solid state solution.

[ben7]

Re: smoothing out voltage spikes and dips?

so my gauge went into commercial service and it seems to be standing up just fine. I am hoping someone is still alive on this thread because I am back And I could sure use a hand with a tune up on my level gauge.

it is for applying voltage to pin 9. with voltage applied to this pin its a bar graph. its great for bright days. with no voltage applied its just a dot gauge. great for at night.

I hooked it up to a relay but I guess after this many clicks back and forth it has died. I am hoping to come up with a solid state solution.

Is the relay switching an AC or DC load? What sort of current is it switching on and off? What voltage is it switching, 12V? Is it switching an inductive load? (I.E., a motor?)

You can use a MOSFET as a switch, they have a low ON resistance, so they are more efficient.

Could you draw up the circuit that this relay is used in?

[stj]

Re: smoothing out voltage spikes and dips?

you want a 0.1uf ceramic across pins 2&3 to minimise switching noise from the led drivers.

[scampo77]

Re: smoothing out voltage spikes and dips?

I could draw a diagram but it is easier to try to explain. There is no current at all, it is just a signal voltage "telling" the IC to light up all of the LEDs or one single LED.

So when I start the car it applies 12v to leg 9, what I need is a way, when I turn on the headlights that it applies 12v/ground to interrupt the 12v signal that is always applied.

I have a bunch of mpsa56 and various other TO-92 cases here I would like to use. I am really out of room on this board, if I must use a relay or to-220s I will have to build it externally.

[ben7]

Re: smoothing out voltage spikes and dips?

I could draw a diagram but it is easier to try to explain. There is no current at all, it is just a signal voltage "telling" the IC to light up all of the LEDs or one single LED.

So when I start the car it applies 12v to leg 9, what I need is a way, when I turn on the headlights that it applies 12v/ground to interrupt the 12v signal that is always applied.

I have a bunch of mpsa56 and various other TO-92 cases here I would like to use. I am really out of room on this board, if I must use a relay or to-220s I will have to build it externally.

Well, you could place a resistor, say 10K, between pin 9 and VCC. Then connect an NPN transistor from pin 9 to ground. The 'emitter' pin connects to ground, and the 'collector' pin connects to pin 9. Then, connect the 'base' pin to the 12V going to the headlights with say, a 10K resistor. If you don't use the resistor there, the transistor will burnout.

When the headlights are turned on, the transistor will turn on and pull pin 9 'low'. Is that what you want to do?

[budm]

Re: smoothing out voltage spikes and dips?

The Voltage applied to pin 9 (BAR/DOT selector) should be from the VCC pin of the IC not directly from the car 12V which can be as high as 14V and spike which can be even higher, and if you have load dump, it will be a lot higher. The 12V voltage feeding to the BASE as Ben suggested will be fine.

[scampo77]

Re: smoothing out voltage spikes and dips?

I think I understand I think this is the solution. So I would be applying ground via the transistor to pin 9 when the transistor is energized? when the transistor is not energized the VCC flows from the PSU through the 10k resistor and energizes pin 9?

Transistors are still a mystery to me. I am at work now and I will try this when I get home tonight.

BudM, Yes it is VCC voltage that comes from 10v I have made at the LM317 regulator.

[ben7]

Re: smoothing out voltage spikes and dips?

I think I understand I think this is the solution. So I would be applying ground via the transistor to pin 9 when the transistor is energized? when the transistor is not energized the VCC flows from the PSU through the 10k resistor and energizes pin 9?

Transistors are still a mystery to me. I am at work now and I will try this when I get home tonight.

Yes that is how it would work.

[budm]

Re: smoothing out voltage spikes and dips?

"I hooked it up to a relay but I guess after this many clicks back and forth it has died." so what died? the relay or the LM3914?