Tagged With "Zener Diode"

Topic

How do you install a zener diode in a ZW Transformer

Lil John ·
I have installed many standard silicon type of diodes in ZW transformers. All of them have worked out without any problems. Now, I have been reading that I may have a better results if I were to use a Zener Diode instead. One of the posts that I have read said to use a 1N3311B 50W 12V diode. Does anyone have any info on this diode as installed in a ZW Transformer.
Topic

Convert 18V AC to regulated DC?

Ted S ·
@gunrunnerjohn and other electronics gurus, I need your help! I would like to build a circuit that "conditions" track power to feed a wireless receiver / decoder that was originally designed for battery RC operation. Let's assume that I'm putting the typical 18 or 19 volts, 60 Hz unregulated AC into the track, with a current capacity of ~8 amps. For various reasons, there may be places on the layout where the voltage at the rail head drops as low as 16 volts. Also, the voltage...
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Re: How do you install a zener diode in a ZW Transformer

Tracker John ·
Why would you use a Zener to generate DC to trigger a whistle? They are used for over-voltage protection, current would be rectified only when the instantaneous voltage is < 12v.
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Re: How do you install a zener diode in a ZW Transformer

shawn ·
Because it works great across the board with old and modern horns and whistles. Air whistles may be a bit softer sounding. I've done this to my 5 ZW's.
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Re: How do you install a zener diode in a ZW Transformer

Susan Deats ·
See Tranz4mr's ZW Page and his Whistle Diodes page.
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Re: How do you install a zener diode in a ZW Transformer

penn station ·
A zener will behave exactly the same as a regular diode in the forward direction. That means when the anode is more positive than the cathode current will be allowed to flow from anode to cathode once you get past the knee voltage, roughly 0.6 to 1.0 volts. This is often referred to as the diode voltage drop. In the reverse direction where the anode is less positive than the cathode both the zener and regular diode will block current flow. So no current will flow from cathode to anode. The...
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Re: Convert 18V AC to regulated DC?

gunrunnerjohn ·
You can likely do this with a very inexpensive buck regulator module from eBay. eBay: 323405451143 , $2.68 shipped free. The Zener diode is not at all suited for this application, but this module should do the trick.
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Re: Convert 18V AC to regulated DC?

BOB WALKER ·
Cannot think of a better or less expensive solution than GRJ's. Having done a lot of R/C work, I was curious to know what brand of decoder/receiver you are using.
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Re: Convert 18V AC to regulated DC?

Severn ·
anything that has a higher amperage rating? you know to drive 2 DC can motors that might sometimes ask for more than 2.2 amps?
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Re: Convert 18V AC to regulated DC?

gunrunnerjohn ·
Look on eBay, lots of choices. Truthfully, I suspect the incidence of the motors drawing 2 amps is pretty small. Also, the supply has overload protection, so it'll just fold back if you stall the motors. In order to get a can RS385 can motor to draw more than 1A on the bench, I have to get a pretty firm grip on the flywheel and really slow it down. My personal opinion is this would be fine, it has a 3A peak output. Output current range: up to 2.2A (the regulator chip can withstand a maximum...
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Re: Convert 18V AC to regulated DC?

Severn ·
Well for my purposes you are right it is probably fine. I've just read these can motors can at stall or power up have a high transient peak ... when i've poked around looking for these voltage converters i've failed to find any that support, oh I dunno more than a few amps. Then again, what I should do is simply get one, use it and if there's a problem -- do something. I will add unexpertedly that the few motors I've played with do seem to run a tad better, especially on the low rpm side if...
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Re: Convert 18V AC to regulated DC?

Severn ·
I should just make one. just buy better parts from digikey. little problem, not exactly sure how but have a just enough to be dangerous inkling. I see a linear regulator in the pic (I think), 2 capacitors, some connectors and a tiny screw dial. then there's the thing with a 470 on it. I have no idea that is -- and another vertical part on the left side flush against the edge and perpendicular to the far capacitor in the pic. I see I think on the right hand side an led, then in front it a...
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Re: Convert 18V AC to regulated DC?

gunrunnerjohn ·
You do NOT see a linear regulator, that is a switching regulator. A linear regulator handling the power you're talking about would be a hot potato! The ferrite coil you see is the inductor for the switcher, the LM2596HV chip. It will run MUCH cooler than a linear supply and also handle way more current than a linear supply that's anywhere close to this size. Truthfully, do you really think you can do better for $3?
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Re: Convert 18V AC to regulated DC?

Severn ·
no i would expect to spend < $100 and possibly learn something though. It's been a vexing problem for me since I don't quite know what to buy or look for, quite what to match up against motors + small cpu (such as an arduino) and motor control boards -- and understand it to be a well understood and easy-ish problem for those in the know. I've been using batteries but they are cumbersome. My 18v ryobi tool battery appears to work pretty darn good but it's the wrong shape. It's ok otherwise...
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Re: Convert 18V AC to regulated DC?

gunrunnerjohn ·
I guess I'm just confused as to why with this statement you'd suddenly decide to start designing your own power modules. I may simply be missing something in the translation.
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Re: Convert 18V AC to regulated DC?

Severn ·
Well I guess what I was getting is that if I don't like the ones you can find readily, I could learn something and just make my own. that's the only pt to it.
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Re: Convert 18V AC to regulated DC?

BOB WALKER ·
Linear regulators are very simple, easy to control, but run hot and need to be carefully heatsunk. As pointed out by GRJ, switching regulators dissipate much less and will run cooler. For a lot of applications, it's a toss-up.
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Re: Convert 18V AC to regulated DC?

gunrunnerjohn ·
With the new single chip designs, switchers are not that hard to assemble, and for any appreciable power, are usually a better choice. For the LM2596HV used in the module I recommended, all it takes is four outside components and for AC input, a bridge rectifier. Not a whole lot more complicated than a linear design.
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Re: Convert 18V AC to regulated DC?

Severn ·
well I found this nifty seeming kit for learners but of course it's a runs hot type... eBay 322392708398 and here's another non kit by the same seller. it certainly looks a quite a bit bigger than the first. funny I don't remember all those heat sinks in my engines. to be fair I never really looked that hard. eBay 323575729524
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Re: Convert 18V AC to regulated DC?

JohnActon ·
So all your locos have DC can motors ? Why not convert to DC track power if you want to use G scale boards designed for a stable DC supply. Seems you are making this more complicated than need be. If you want AC on the track why not use ERR TMCC boards ? j
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Re: Convert 18V AC to regulated DC?

JohnGaltLine ·
If you can find a ready made board that does what you need, they are almost always the best choice from a cost and size perspective. Most of the time I can't find the parts for twice the cost of such boards. As for learning how to build basic circuits like buck/boost converters, linear regulators and deciding when to use each, there are countless resources online, often as simple as typing your question into youTube's search bar. I'll recommend Jeremy Blum's introduction to Arduino for a...
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