Heatsinks

1) Surface Area and (2) Thermal Resistance of the heatsink.

1] Surface Area : The surface area or area exposed to atmosphere is made to a maximum for particular particular design considerations. Theoretically 1800 Sq.mm. of totally exposed aluminum is sufficient to dissipate one watt of heat generated without appreciable change in temperature. This can be used as a rough guideline keeping in mind the actual design of the heatsink and actual area exposed to atmosphere. Closely spaced fins from heat pockets, thus obstruction convection flow They also adversely affect heat transfer by radiation

2] Thermal Resistance : This is more reliable base, if certain set of conditions are maintained Thermal resistance of a heatsink can be obtained by, Qr = (Ts-Ta)/P

Where Qr is the thermal resistance, Ts is temperature of the hottest point on the heatsink (nearest to the mounted semiconductors), Ta is the ambient temperature and P is power applied to the heat generating semiconductor. Thus lower the value of thermal resistance, the more effective is the heatsinks

There are other factors which affect the efficiency of the heat transfer, which could be listed below;

1] Mounting of Heatsink : Mounting should help expose as much area as possible with fins vertical and away from other heat generating components (Transformers etc.)

2] Surface Treatment : Black anodised heatsinks are known to increase the efficiency by at least 25% in case of natural convection. Painted surface affects the efficiency adversely. Whereas, heatsink surface can be finished in Black, Natural Anodizing or could be chromotised

3] Contact Resistance (Thermal) : Between the semiconductor case and heatsink. Proper 25% in case of natural convection. Painted surface affects the efficiency adversely. Whereas, contact resistance considerably thus increasing the efficiency.

4] Ambient Temperature & Air Movement : Higher atmospheric temperature naturally decreases heat transfer efficiency. Similarly adequate air movement or forced convection by blowing air over heatsink or sucking hot air from heatsink improves heat transfer abilities to great extend

Our Product Range shows the profiles of various sections available with us and important dimensions. The surface area and Thermal Resistance is mentioned next to each of our heatsinks, should give you the base for selecting an appropriate heatsink

Lenghts mentioned in our product range are only standard, besides which we can supply these sections in any lengths upto 1000mm as per requirement. The semiconductor mounting holes are suitably placed on standard lengths, but can also be drilled/tapped/ machned as per customer's requirement.

The semiconductor mounting central strip of any section or contact area of semiconductor Mounting can be given in unanodized (masked) finish.

We also undertake to develop heatsinks to suit customers requirement for large quantities.

Our product range gives you the complete idea of heatsinks available with us.