I
introduce the temperature regulator(Thermostat) which used a thermistor
for the temperature sensor. This circuit can control a outside system by
driving a relay when the temperature of the thermistor becomes a setting
temperature. The strict temperature setting can not be done with this
circuit like the thermometer. The resistance value of the thermistor
changes by the ambient temperature. This circuit changes the change of the
resistance value into the change of the voltage using the transistor.
Then, it compares that voltage and the voltage of the setting temperature
using the voltage comparator and it drives a relay. It is a relatively
simple circuit. With this circuit, the difficult point is to handle an
analog signal (the temperature change). The characteristic of the
thermistor, the transistor and so on has an influence on the performance
of the equipment just as it is. Even if the thermistor or the transistor
of the same name is used, the same performance (the setting temperature
range and so on) isn't sometimes gotten. The design to have considered the
ruggedness of the part is possible. This time, I made a circuit based on
the result which measured the characteristic of each part. I think that
this way becomes reference as the case when there is not data of the
part.
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