This circuit, is basically a resistance � sensing window switch, except that the �resistor� takes the form of an NTC thermistor and the circuit thus responds to temperature. TH1 must have a resistance in the range 500ohm – 9Kohm. RV1 is used to set half � supply volts on the RV1 � TH1 junction at the �mean� temperature
Part List
R1=4.7Kohm TH1=NTC thermistor 500ohm…..9Kohm Q2=BC214L
R2=2.2Kohm D1-2=1N4148 RL1=12V Relay >120ohm
RV1-2-3=10Kohm pot. D3=1N4001
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Read more source:
http://users.otenet.gr/~athsam/temperature_window_switch.htm
Thank you.
This entry was posted on Tuesday, October 16th, 2007 at 11:31 pm and is filed under 741, Electronic Control. You can leave a response, or trackback from your own site.
