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Old 10-12-2010, 07:15 PM
Guruji Guruji is offline
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Join Date: Aug 2008
Posts: 849
Mosfet heater

Originally Posted by gadh View Post
Hi all.
i hope this is the right thread to post for this subject.
i'm continuing my tests on the Ainslie (MOSFET heating) circuit, after a few months i did not have time to promote this issue.
now i'm in the middle of the heat testing. first i tested in an equivalent DC circuit, in which i adjust the current to be stable at rates of 200/400/600 ma, and i measure the heat rise by time with a multimeter and k-type thermocouple probe. the probe is measuring the temperature rise of a distilled water tank (650cc) in which i put the load resistor.

so far no problem. but now i started testing the Ainslie circuit which uses pulsed DC current, and the multimeter shows weird results ! it jumps immediately to 36 degrees (all celsius) (while ambient is 24 deg.) and then almost immediately to 50-70 deg. and continues to fluctuate between these values. the actual water remperature does not change in this time. the probe does not touch the load resistor and the water resistance is between 1-2 megaohms (this value also changes , depending on the scale i choose - 2 mohms, 20mohms, and also by time it changes, so its weird too...).
the distilled water label shows "0 micro-siemens".

could someone help me understand why the heat measuremnt goes crazy ?
Hi Gadh it's amazing what you're saying so do you mean that if I put a JT to this circuit I can hook it to a water heater?I understood rightly?
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