Hello,
One of the things that will prove to be useful to me is a resistance box. Now I know I could buy one, or a programmable load, but I'd rather make my own. I'll learn more this way.
Now I have two options for creating one.
1: Use resistors.
2: Use a MOSFET (or maybe an IGBT).
Now for a 1/4w box, resistors would be the obvious choice, but if you want something that can handle more power, say 100w, then resistors require heatsinks and become quite expensive. That is not to say that I'm actually planning to throw 100W at a resistance box, rather, I'm fairly certain that is the upper limit of what I'd use it for throughout my lifetime. Even at half that power level, resistors require heatsinks and are themselves expensive.
Not that it's the ideal part, but the ever popular IRFZ44N can dissipate 110W, theoretically. The problem is dissipating the heat.
So, I started reading up on the various heatsinks. I have learned that fin length (often the height), is very important for cooling.
A good example of a heatsink for MOSFETs is the Ohmite brand RA and FA series (datasheet). But they're rather expensive compared to plain stock extruded heatsinks you can find online. For example (HxWxD/L), XXx34x12mm TO-220/TO-247, 36x69xXXXmm, 25x60x150mm, and 6x20xXXXmm.
(XXX is typically 50, 100, 150, 200, or 300, millimeters with the noted exception of the TO-220/TO-247 model listed above which comes in several sizes. I've noted sizes of 38, and 70 millimeters, as they correspond roughly to the size of the Ohmite variety, but the generics are only half as deep and about 3/4 as wide).
Which brings me to my question, has anyone characterized the thermal performance of no-name heatsinks? I did try searching online, but I'm just not getting anything useful.
Thanks!
One of the things that will prove to be useful to me is a resistance box. Now I know I could buy one, or a programmable load, but I'd rather make my own. I'll learn more this way.
Now I have two options for creating one.
1: Use resistors.
2: Use a MOSFET (or maybe an IGBT).
Now for a 1/4w box, resistors would be the obvious choice, but if you want something that can handle more power, say 100w, then resistors require heatsinks and become quite expensive. That is not to say that I'm actually planning to throw 100W at a resistance box, rather, I'm fairly certain that is the upper limit of what I'd use it for throughout my lifetime. Even at half that power level, resistors require heatsinks and are themselves expensive.
Not that it's the ideal part, but the ever popular IRFZ44N can dissipate 110W, theoretically. The problem is dissipating the heat.
So, I started reading up on the various heatsinks. I have learned that fin length (often the height), is very important for cooling.
A good example of a heatsink for MOSFETs is the Ohmite brand RA and FA series (datasheet). But they're rather expensive compared to plain stock extruded heatsinks you can find online. For example (HxWxD/L), XXx34x12mm TO-220/TO-247, 36x69xXXXmm, 25x60x150mm, and 6x20xXXXmm.
(XXX is typically 50, 100, 150, 200, or 300, millimeters with the noted exception of the TO-220/TO-247 model listed above which comes in several sizes. I've noted sizes of 38, and 70 millimeters, as they correspond roughly to the size of the Ohmite variety, but the generics are only half as deep and about 3/4 as wide).
Which brings me to my question, has anyone characterized the thermal performance of no-name heatsinks? I did try searching online, but I'm just not getting anything useful.
Thanks!