The water temperature regulator bring to your attention a rather simple scheme water temperature regulator , which can be useful in a private home near her house to heat water in a storage tank for household needs. Method of regulation-off: Enable or disable the heaters using a relay. Details: -KT315 transistor with any letter index -KT815 KT817 can zaminty on or KT805-Zener diode with a 20-30 -D1-D3 virtually any silicon bass -S5, S6, for a voltage below 400 In -C3, C4 capacity from 4.7 to 5.6 uF for a voltage below 400 V of energy-saving lamps, compact -relay coil to contacts 24c and 5-10 A Principle of operation: Resistor R2 adjusts the bias voltage to the input of the amplifier transistors V1 and V2. The transistor V1 depends on the temperature of its body temperature above -large conductance transition. When power is applied and installing R2 temperature setpoint relay and their contacts delivers a voltage to the shadows and begins heating. Upon reaching the desired temperature, the conductivity of the transistor V1 changes that leads to closing of transistor V2 and relays water cools off. Reaching a certain temperature relay is switched on again and the process repeats. Temperature fluctuations of water is less than 5, 5 ° C. diodes D1-D3 assembled voltage regulator to prevent failure temperature setting, since there is a slight activation of relay planting voltage, which significantly affects the temperature setting. C4 prevents interference to the amplifier input. The device is powered by AC 220 V. After quenching capacitors C3, C4 and shunt diodes D5, D6 AC voltage is applied to the diode bridge and stabilized to a value of 24V zener. The length of the wire to the sensor is not more than 1m, and at greater length should be shielded wire. Board mounted with the items in a convenient package, the front panel potentiometer output indicator and power switch. Graduation potentiometer to be done with a thermometer 20 -100 ° C. If necessary, the control range can be shifted, narrow or expand through limiting resistors R1 and R3. Photos PCB Download PCB format LAY Attention! Be careful control is not isolated to the network, so when his work does not touch the parts of it. V1 sensor must be insulated!