Electronic relays [india] began its endeavor by exporting a major part of its production to the united states. Electronic relays [india] pvt ltd offer power proportional controller. The proportional controller is made to control the power delivered to the load. The power fed to the load can be controlled by applying control voltage 0-10 v or by supplying 4-20 ma current.
Synchronisation circuit gives sync pulses for duration 400 to 500 nano sec and every 10 milli seconds. The output of the synchronisation circuit is given to the ramp and resets at the next sync pulse. The ramp is fed to the pulse width modulator, which controls the width of the output square wave according to the v dc input, which is obtained through buffered and inverted circuit.
Additional block current to voltage converter is added for 4-20 ma input. The pulse is fed to the firing circuit, which fires the back-to-back scr/triac/alternator. Since the firing angle is related to the v dc linearly, power delivered to the load is linearly to the v dc linearly; power delivered to the load is linearly proportional to i/p fed to 0-10/0-5 v dc or 4-20 ma dc.
