hey i'm looking for a heatsink that will fit snugly on a tip102 transistor any suggestions? I'm trying to have it as small as possible
Boy, where to begin? You can have a small heatsink or an efficient heatsink. You're going to have to trade off one for the other. Anywhere from this:
to this:
and everything in between.
What are your space constraints and your cooling requirements? How much heat is the TIP102 going to dissipate?
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tege88:
hey i'm looking for a heatsink that will fit snugly on a tip102 transistor any suggestions? I'm trying to have it as small as possible
RuggedCircuits is right in that before you can decide on a heatsink, you need to figure out your requirements, and it will ultimately be a trade off in size vs. efficiency.
With that said, you might be able to get away with a homebrew solution; a small piece of U-channel aluminum, drilled with a hole, with the walls of the channel slotted (use a hacksaw, file and drill for all of this), lapped with some sandpaper, and a small amount of heatsink grease; then just bolt it to the device. All in all, you could probably get the parts needed much cheaper than buying an equivalent heatsink, and the piece of U-channel will make several such sinks.
hey guys,
thanks for getting back in touch, basically I'm using this tutorial:
Arduino Playground - HomePage to drive 10 solenoids i was going to create the circuit in a way so that when i put it on stripboard it fits on top of the arduino (if you know what I mean)
The thing i'm not sure about is that I have tested the circuit without a heatsink for about 15min and it was fine, what I'm worried about is this thing is going to be for 8hours a day however the valve is opening and closing constantly so therefore requiring less power.
What would you recommend to do?
The TIP can handle 4Amps (looking at the circuit), Do you have an datasheet of the solenoid ?
It should tell how much current it uses...
If the circuit is turned on for 15 minutes and doesn't heat up much, it will probably be OK though, 15 minutes is quite a lot for a small piece of metal to heat up. It would heat up much faster and get a lot hotter if too much current flows. Too much heat isn't good, but even when it begins to feel hot (and doesn't heat up further), the transistor is probably able to handle it.
hey,
here is the datasheet
http://docs-europe.electrocomponents.com/webdocs/03a0/0900766b803a09fa.pdf
The sheet doesn't tell the current, but we can calculate that.
According to the sheet, the power draw is 6VA. (or watts, that's the same...)
Powerdraw can be calculated by multiplying Voltage x Amperes.
In reverse, dividing power draw by the voltage will give you the nr. of amperes.
The 12 volt one will there for draw 0,5 ampere (6/12=0.5) and the 24Volt one, same power draw, 0,25 amperes. It's recommended to use a transistor capable of driving 1.5 - 2 (or more) times the power it handles.
The TIP is therefor more as capable enough and there's no real need for a heatsink.
You could probably even drive 3-4 solenoids using the same Transistor safely.
great!
Thanks very much for your help.