Quote:
Originally Posted by rcheshire
Jo. Just use a thermometer to measure the ambient temperature and then hold it in the heatsink exhaust. 10C differential is good. If you are doing better than that then you could use a bigger TEC without modifying things too much.
PWM or linear are the two methods of control. I find PWM much easier to manage having spent a lot of time recently dicking about with linear. When you get out at night it's a pain to adjust to maintain a consistent set temperature.
PWM is more complex - you need some form of pulse generator, either a 555 timer and potentiometer or a microprocessor, to generate PWM an NPN transistor, MOSFET, resistors capacitors and an inductor. I will post an updated circuit, once I get it tuned up.
PM me if you want to discuss some options.
I'm getting setpoint +/-0.2C - which is great for darks.
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Thanks Rowland,
I'm getting around 5c difference between the heat sink and ambient air temp.
How does the PWM know how much to adjust the the power to keep the temp the same? Is it connected to something else?
I got a 12v PWM temperature controller on ebay thats got a temp sensor, and also a screen and buttons so you can set the temp differences and stuff, I think it can keep with in 1C so I'm interested to see what it's like. It might not work but as it was only 15 bucks I thought see what its like.
Should arrive next week, I can post a link if you like.
Sorry, love to PM you but I don't have an email address
Cheers
Jo
PS. The temperature controller is
this