Thermostat circuit with SCR TIC206M

thermostat circuit with SCR

The temperature fluctuations are indicated by an (1.7K @ 70F) thermistor position in series with a 5K potentiometer which approximately 50 mV / degree F at the entrance to the LM741, comparator A. The two 10K resistors to pin 7 of voltage is the same as in half the supply voltage and the hysteresis range, or about 3 degrees of 150 millivolts. The beach hysteresis (temperature range, where the obligations and sold relays) can be connected to the 10K resistor between pins 1 and 7 A higher value reduces the stretch.

In operation, the resistance is set so that the relay switch, comes to the desired temperature. A drop of three degrees the temperature should be moving to on the back and to stay until the temperature rises back to the level materialize. The relay action can be reversed, so it switches from the lower field by reversing the position of the 5K potentiometer and thermistor. The Z-diode 5.1 volt circuit regulates the voltage so that small changes in the provision of 12-volt-effect does not work. Tension in the thermistor should be half the supply, ie about 2.6 volts when the temperature by 3 degrees within the range set potentiometer. Most everything thermistor can be used, but the resistance is greater than 1K ohm at the temperature of importance. The resistance must be two times the resistance of the thermistor when the adjustment ends in the vicinity of the headquarters.