Does this voltage regulator need a heat sink?

[Ghost Planet]

I'm building this voltage regulator and was wondering if the IC needs a heat sink. The input voltage will be 14 volts. Here is the link to the schematic.

https://www.google.com/search?q=9+volt+regulator&hl=en&safe=off&client=safari&tbo=d&source=lnms&tbm=isch&sa=X&ei=h1PwUOPjOIT48wSplYCQCQ&ved=0CAgQ_AUoAQ&biw=480&bih=268#i=4

[R.G.]

In many situations in electronics, what has to be inside a circuit depends a lot on what it outside it. That is the case here.

If you build the circuit as shown, no, it absolutely does not need a heat sink, but only because it shows no loading on the regulator at all. With no loading, the regulator will happily sit there forever, putting out a regulated 9V that nothing uses, and having almost no heat rise.

But regulators with no load are kind of useless. You're planning to put a load on it of some kind. The load will draw a load current and that must flow through the regulator, heating it up. How much it heats it up (and therefore the answer to "does it need a heat sink"") depends on how much load current flows.

Without knowing the load current, you can only assume some value as a maximum you think will happen, and then from that figure out whether so much heat is generated that it has to have a heat sink.

So - what's your maximum load?

[Ghost Planet]

Do you mean amps when you say load? The power supply is 5 amp

[Ghost Planet]

I will be driving a 9 volt distortion pedal. The regulator will be inside of a tiny giant amp. Here is a link to the amp schematic.http://musicpcb.com/wp-content/uploads/2011/02/Tiny-Giant-Build-PDF-rev2.pdf

[R.G.]

I do mean amperes when I say load, but it's how much current comes out of the 9V side that matters, not how much the power supply on the 14V side can possibly produce.

In your case, you're telling me that you will only put one distortion pedal on the 9V side. What is important is how many amps the distortion pedal uses. At a guess, it's probably less than 50ma, as most of them are that small. In that case, no, you don't need a heat sink.

If you meant "I'm only putting one small pedal on the 9V side now, but in the future I'm going to gang up lots more pedals on it" then, you probably do need a heat sink, because each pedal you load onto the 9V will suck some current of its own and the regulator has to supply them all.

[arawn]

what i think rg means is put a heat sink on it. Then no worries!

[gcme93]

Very simple theory for how the current thing works:

Your power supply (wall plug or 9V battery etc) only provides the circuit with how much current it needs. For your case, the supply could do 4A if it needed to, but if it is only being asked for 100mA for a distortion pedal, that's all it will provide.

As a bit of context, the Tiny Giant voltage regulator needs a heat sink because thats drawing a few amps - the more current, the hotter it gets. Your new voltage regulator that you're adding should be fine without a heat sink, but why not add one anyway, if you're already doing it with the Tiny Giant? It will be one less thing to worry about if you decide to use the 9V voltage for more strenuous uses.

Hope this is clear!

[Ghost Planet]

I do like the Boy Scout motto, so I'll go ahead and attach one. I have an aluminum back from a radio shack plastic project box that I can cut and turn into a simple heat sink. I plan on building the tiny giant, adding a big muff tone control with the body control from beavis audio and a new clipper from ROG powered by the voltage converter. I'll take pics when it gets finished. Thank you so much for the help everyone.

[Jdansti]

You could also bolt the regulator to the metallic enclosure since the metal tab is connected to pin 2 (ground).

[PRR]

Your link is a search for ALL images of ALL voltage regulators.

I will ass-ume you are using the 78xx type chips. They have protection. They shouldn't have fatal voltages on them.

The cave-man way to answer your question:

First build it with a 2.2K resistor where your load will go. Verify proper output voltage (this is sometimes the tough part: pinouts, joints, etc). Then connect your load. Lick your finger. Touch the regulator.

If your finger sizzles, you need a heatsink.

Yes, there are more elegant ways to test, even predict.

[Perrow]

Ah, there's a finger licking answer if I ever saw one

[Kesh]

No idea what regulator you're using, as your link goes to google. And your tiny giant shows a different voltage regulator doing a different job. So I'm a bit confused.

I think a TO-220 can dissipate about a watt without a sink

1W/(14V - 9V) = 200mA

So if you are using 200mA or more I'd use a sink, maybe even a bit less than 200mA to allow for variation and general back-of-an-envelope calculations.