Advertisements

Archive for March 10th, 2012

Peltier PWM Temperature Control: MOSFET Thermal Block

The Peltier assembly looked like this while I was epoxying everything together with JB Weld:

Peltier module - epoxy curing

Peltier module - epoxy curing

The aluminum-case resistor held the heatsink at 105 °F to encourage the epoxy to cure in a finite amount of time.

The 40 mm square block is a squared-up piece of 1/2 inch aluminum plate (manual CNC on the Sherline, nothing fancy) with a pair of 6-32 tapped holes for the screws that will hold TO-220 transistors or the yet-to-be-built TO-92 adapter. The CPU heatsink got a pair of symmetric holes for the posts holding it to the acrylic base, but other than that it’s perfectly stock.

MOSFET thermal block - drilling

MOSFET thermal block - drilling

Then epoxy the thermistor brick to the middle of the block between the two screws, stick on some obligatory Kapton tape to prevent embarrassing short circuits, and add a foam collar around the Peltier module to insulate the block from the heatsink:

MOSFET thermal block

MOSFET thermal block

A square foam shako covers everything, held down with a random chunk o’ weighty stuff, to insulate the whole affair from the world at large.

Advertisements

,

1 Comment