Circuit Project Electronic

The circuit is small regulatorof temperature, us warns for the increase of temperature. The control of temperature becomes from the thermistor TH1, that is negative factor. His resistance is altered between in the 10K in temperature 25° C and roughly in the 1K in their 94° C. The trimmer TR1 regulates the precise temperature in which the Q1-2, connected as darlington, conduct, making him relay K1 close also the buzzer BZ, sound. The alarm is activated when the temperature becomes bigger than predetermining. The thermistor it should he is placed far from the remainder circuit, in order that this is not in danger from the temperature. The supply of circuit becomes from battery 9V, but if he is placed in constant place, then we can him supply with one power supply . In the contacts of relay we can connect what load we want, as a lamb, other circuit k.a. Also can is added a LED, if we want to have also optical clue of excitation. The regulation becomes sinking him thermistor TH1, in water which we know the temperature of (the contacts should are well insulate so that do not have short-circuit) and regulating him trimmer, until excited the circuit. The cable that we connect the circuit with the TH1, should be plate.

Related Links
More circuit Temperature Control
More circuit Electronic Control
Digital Measurements Temperature by LM335
More circuit about Meter
Optical Power Meter by IC 741
Digital Step-Km Counter with IC 4026,4024
Test Transistor in Circuit by IC 4011
High impedance DC Voltmeter by IC CA3130
Light Sensitive Switch with LDR + 2N2926
Peak Level Indicator by IC LM723
AC Line testing circuit.
Car Temperature Gauge by IC CA3162 + CA3161

Read More Source:
http://users.otenet.gr/~athsam/high_temperature_alarm.htm