There are many management schemes chandelier by two wires. Listed here the scheme is characterized by its simplicity and, hence, affordability and small size. It is completely housed in decorative cover chandeliers.
The principle of the scheme next
When switched on the chandelier temperature of the thermistor R2 is equal to the ambient temperature and its resistance is relatively high, the voltage at the relay exceeds the voltage, and it is their contacts breaks the circuit, the power light HL1-HL3. After a few seconds the resistor R2 is heated by passing current through it and its resistance decreases, the voltage at the relay drops to the value U1, which should be a little more stress retention, but definitely less than the trigger voltage. Now if for a short time (0.5 to 1.5 sec) power off the chandelier, the resistor R2 will not have time to cool off and when switching the voltage to the relay is shorter than the operation voltage, the contacts will remain closed, and the network will be connected all six lamps. To again put the device in mode "half" turn on, to turn off the power to the time required for cooling of the thermistor 2 to 3 seconds). The scheme is built into the chandelier with six bulbs over 40 watts and it always works for about ten months.
In the scheme we used the following parts. Relay K1 is compact with a coil resistance of about 300 Ohms, a voltage of 7 V and a voltage drop of 3 In (it is advisable to choose the relay with the highest hysterisis). the resistor R2 to three thermistor connected in parallel ST3-17 the resistance to 1 Ohm each (a good one just was not at hand). The resistor R1 type MLT-0,25 resistance of several tens of Ohms might need to set the voltage on the relay (in steady-state hot) a little more stress retention. Diode Assembly used type CCA. The capacitor C1 is 50mkf x 16 V. All parts are mounted mounted Assembly on the findings of the relay.
Author: A. Nazarov (RA4UEL), Saransk; Publication: N. Bolshakov, rf.atnn.ru