Archive for the Category


200W PC power supply switching 110V-220V

Sunday, August 10th, 2008
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This be PC power supply for Computer again interesting circuit. May advantage with friends at do an occupation can repair a computer? By think be the character Switching power supply 200W sizes take AC Voltge Source 2 level be 110V and 220V choose can use leisurely. And still use volt [...]

Thermocouple to RS-232

Sunday, June 22nd, 2008
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In this circuit, the LT1025 cold-junction compensator provides the signal conditioning. The compensator’s voltage varies with the temperature of the reference junction in such a way that when summed with the thermocouple voltage, the combination behaves as if the reference junction were maintained at 0°C. (You should place the compensator as close as possible to [...]

RS-232C digital thermometer

Friday, June 20th, 2008
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Accuracy depends only on the tolerance of the nominal 10-to-1 R1/R2 ratio. Temperature-to-digital conversion involves a voltage-to-frequency-ratio scheme: Difference amplifier IC3 compares the square wave from Q1’s emitter to the signal developed across R3 by switches IC2A and IC2B, acting concurrently with R4, R5, and the 2.500V reference IC4 develops. IC3 amplifies the difference with [...]