Where to buy heatsinks for multiple devices - Page 1
Forum section: electronics / projects

author: tom66
author_rank: Super Contributor
timestamp: December 09, 2014, 09:57:38 pm
content: I'd like to heatsink multiple TO-220 devices. It seems like a sensible option would be to have one large heatsink will all devices mounted to it, rather than individual ones. Total power dissipation will be on the order of 10W total.Does anyone know where you can buy these? Devices like these:The PCB design will mostly be decided by the heatsink, so the exact dimensions aren't critical.The unit I'm building will have fan cooling.I have some boards I can take heatsinks off, but I want to make more than 1 unit, so I need to buy them from somewhere...

author: Thor-Arne
author_rank: Unknown
timestamp: December 09, 2014, 10:20:48 pm
content: RS have some like that, made by Fischer Elektronik.

author: tom66
author_rank: Super Contributor
timestamp: December 09, 2014, 10:30:52 pm
content: Thanks! This looks ideal...http://uk.rs-online.com/web/p/heatsinks/1898331/Reading the graph I presume that I need to look at the length property (in this case 84mm) to get the C/W for a given heatsink, about 3.5C/W.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 09, 2014, 10:41:15 pm
content: http://www.aavid.com/

author: Neilm
author_rank: Super Contributor
timestamp: December 10, 2014, 06:48:43 pm
content: A word of warning - TO220 packs can have conductive tabs so ensure that they can either be connected together or are isolated from each other.

author: Yansi
author_rank: Super Contributor
timestamp: December 10, 2014, 06:53:20 pm
content: I don't think he is so stupid.

author: tom66
author_rank: Super Contributor
timestamp: December 10, 2014, 08:10:08 pm
content: Quote from: Neilm on December 10, 2014, 06:48:43 pmI'm aware of this. One more thing to be aware of. I had inserted the screw insulators in (that came with my mica insulators), but if you do not get the screw in perfect, or if it's a little too big, it will short devices together.Luckily, found this with a bulb tester, before plugging in the power supply proper!

author: nali
author_rank: Frequent Contributor
timestamp: December 10, 2014, 08:49:00 pm
content: These guys have a fair few options...http://www.birminghamaluminium.com

author: Yansi
author_rank: Super Contributor
timestamp: December 10, 2014, 09:20:19 pm
content: Do you know about any chinese heatsink suppliers? These fancy local ones are good, but mostly fucking expensive. Would be interesting if such china supplier selling worldwide for reasonable prices existed.

author: tom66
author_rank: Super Contributor
timestamp: December 10, 2014, 09:53:57 pm
content: £2.50 is pretty fair for a heatsink that looks as good as the one Fischer supply. I'm actually pretty surprised it's that cheap, to be honest. Risk of getting one made from inadequate material from China (steel sold as aluminium anyone?), and the shipping time... for a low quantity project it isn't worth it.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: December 11, 2014, 12:14:24 pm
content: Tom,I would suggest looking for a heatsink that uses clips instead of screws.1) It is much easier to get isolation.2) The pressure is over the die in the device3) You do not have to drill and tap the heatsink.4) You have some freedom to place the devices.This style of heatsink may require a fan.Regards,Jay_Diddy_B

author: tom66
author_rank: Super Contributor
timestamp: December 11, 2014, 11:27:30 pm
content: Thanks Jay, do you have any sources? Clips do look nicer and easier to use. Power dissipation is not that high (the fan cools another device too) so I am not *massively* worried about the lowest device-heatsink thermal resistance, but every bit helps.

author: envisionelec
author_rank: Frequent Contributor
timestamp: December 18, 2014, 02:01:44 am
content: Quote from: tom66 on December 10, 2014, 09:53:57 pmIs there any truth to it? ie: what is your experience?