Zener diode for coin door and ipac

[Turnarcades]

Hi. I need to get a replacement zener diode for my coin door from Ultimarc. Unfortunately I know dick about resistors and all that.

Does anyone know the exact zener diode I need for connecting this coin door to an ipac? It needs to go from a 12v signal to a 5v signal......

[mountain]

i would use a 5volt regulator from Radio Shack.

Not sure of the excact use you are going for but it will accept 12volts and output a steady 5volts.

Cheap too 

[mountain]

Oops! Just noticed that you are in England. These are fairly common, you should be able to locate one rather easily.

[Turnarcades]

yeah forgot to say - uk only!

Is a 5 volt regulator fitted differently?

[Kevin Mullins]

I need to get a replacement zener diode for my coin door

So do you actually have one now that you are trying to replace?

If so, then it should have some sort of marking on it, like a letter and some numbers.

It needs to go from a 12v signal to a 5v signal......

Are you trying to reduce the voltage from a 12v source?

You might need to better explain the purpose of this "diode" that you need.
Is it for a coin counter/meter purpose?

[hanelyp]

i would use a 5volt regulator

Is this to convert a 12V power supply to 5V, or a data signal?  The regulator is designed for translating power, and I wouldn't expect the regulator to do so well on a quickly changing signal.  Is there any reason the coin door won't work with 5V?  For signal conversion I'd probably use a 10k resistor in line with the signal and a generic 5V zener on the ultimarc side.  What happened to the original zener?

[SavannahLion]

Guys, just take a look at Ultimarc's website. The OP is talking about Ultimarc's door. There's an illustration there that shows where the zener is supposed to go. It's being used as a shunt.

My apologies to Ultimarc if direct linking is not desired


I haven't experimented with Zeners yet, but I think you need to use one rated with a break down voltage of about 5v to get what you want. It shouldn't be a problem, but I think you need to ensure it can handle over 12v as well.

Oddly enough, the few diagrams I've seen where the Zener is being used as a shunt like this also uses a resister in series, but Ultimarc's diagram doesn't use one. Might be something you want to ask about.

Have you tried emailing Ultimarc and getting better details from him?

[DaOld Man]

Zeners need to have a series resistor to limit the current flow thru the zener.
A zener regulates voltage by "closing" at its rated voltage. ("Clipping" the voltage to the zeners rated volts.)
Thats why the resistor is needed, so that the zener is not passing more current than it can handle while in the closed mode.
Im not sure what ultimarc is doing in this setup, looks like the zener is going across the coin switch signal, so it probably has current limiting circuitry inside the "black box".
The zener is probably there to regulate the volts to 5 for computer inputs.

Here is a link to a very handy site that allows you to figure out what you need to build a zener voltage regulator:

http://www.opamplabs.com/zenerreg.htm

[Beley]

1N4733

there are of course many other that would fit the bill but this seems to be the most "standard" one.

[SavannahLion]

Im not sure what ultimarc is doing in this setup, looks like the zener is going across the coin switch signal, so it probably has current limiting circuitry inside the "black box".

I puzzled over this too. The only thing I can think of is the +12v is just a signal line with low amperage. Hard to say without testing it for myself. He probably left off the resistor because there probably isn't enough current to damage the zener.

Like I said, ask Ultimarc. He hangs out here often enough.

[AndyWarne]

No coin mechs I have come across pull the coin signal directly to 12 volts when there is no coin, its an "open collector" output, usually pulled up in the mech by a fairly high-value resistor. So using a zener in this way is perfectly OK.
Andy

[Turnarcades]

Hi everyone and thanks for the input. You can see the installation from the diagram shown a few posts above. I did try you Andy but the replacement never arrived. Thanks to the person who posted the part number, I will try to get one from somewhere - all I needed was the part number!

[Turnarcades]

Additional.....

I tried a 5v regulator; didn't work. Killed the coin signal completely.
The replacement diode can be had from Maplin. It's a 5.1v, 0.5A zener diode, and costs about 12p.