Hi everybody
I am working on a project permanent fault indicator at domestic level.
Diagrams for circuits are attached please
Objective is to indicate( neon bulb will glow) existence of short circuit at any time in circuit
Circuit operation
When there is a short circuit across load(point a b in picture) ,then circuit breakaer trips.now path of current is through neon bulb(connected in parallel with breaker) .So neon bulb glows and indicate there is a fault.
But when there is no short circuit and circuit breaker accidently trips(due to fault breaker) ,now neon bulb still gets ON as path is completed through neon bulb and load resistor(small value like electric iron having milli ohm resistance).So as there is no short circuit but we are getting indication that there is fault.I have to rectify this problem.
For this purpose i am using opamp (differential opamp) to sense voltage across load ressitor(point a b) and compare it with reference say O volts,when Vab>0 (no shortcircuit), output of opamp should go high and drive a relay or transistor to break path for neaon bulb throug a dry contct shown in figure.
but i am unable to get output from opamp to drive a relay.please advice me how to deal with above problem.Thanks
I am working on a project permanent fault indicator at domestic level.
Diagrams for circuits are attached please
Objective is to indicate( neon bulb will glow) existence of short circuit at any time in circuit
Circuit operation
When there is a short circuit across load(point a b in picture) ,then circuit breakaer trips.now path of current is through neon bulb(connected in parallel with breaker) .So neon bulb glows and indicate there is a fault.
But when there is no short circuit and circuit breaker accidently trips(due to fault breaker) ,now neon bulb still gets ON as path is completed through neon bulb and load resistor(small value like electric iron having milli ohm resistance).So as there is no short circuit but we are getting indication that there is fault.I have to rectify this problem.
For this purpose i am using opamp (differential opamp) to sense voltage across load ressitor(point a b) and compare it with reference say O volts,when Vab>0 (no shortcircuit), output of opamp should go high and drive a relay or transistor to break path for neaon bulb throug a dry contct shown in figure.
but i am unable to get output from opamp to drive a relay.please advice me how to deal with above problem.Thanks
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