I am trying to sense the power factor angle using microcontroller.

Now the mechanism that I have thought it that

1. Measure the zero crossing of voltage
2. When the voltage zero is sensed, start the timer of micrcontroller and then start sensing the zero of current.
3. But how to sense zero of currrent? By using a zero crossing current circuit

My problem: I have made zero voltage circuit using transistor and opamps. The transistor is dependant upon the voltage applied between the emitter and base.When the voltage is zero, the transistor is off and the collector 5 V pulse is obtained accross collector and emitter.

But what for current? Is there any electronic device that is turned on/off by current ?

So I think the only solution is to convert the current into voltage and then sense the zero of voltage. Is it a viable solution?

I am trying to sense the power factor angle using microcontroller.

Now the mechanism that I have thought it that

1. Measure the zero crossing of voltage
2. When the voltage zero is sensed, start the timer of micrcontroller and then start sensing the zero of current.
3. But how to sense zero of currrent? By using a zero crossing current circuit

My problem: I have made zero voltage circuit using transistor and opamps. The transistor is dependant upon the voltage applied between the emitter and base.When the voltage is zero, the transistor is off and the collector 5 V pulse is obtained accross collector and emitter.

But what for current? Is there any electronic device that is turned on/off by current ?

So I think the only solution is to convert the current into voltage and then sense the zero of voltage. Is it a viable solution?

@Andy AKA

1. Convert voltage and current to digital.
2. Sample the V and I at much much higher rate-more than 2 times of 60hz ('dont stick close to nyquist:-)') .
3. Apply low pass filter to the voltage and current.
4. Apply atleast 6 LP filters,so that I can remove harmonics and get pure 60 Hz wave.
5. Now I have V and I.
6. Find Vrms and Irms.
7. Do cosQ=VI/(VrmsIrms).

Doubt: In order to sample current, I must use current transformer(to lower the current) and convert it to voltage and then use a 12 bit ADC or is a ADC avaliable that can directly convert current input to digital?

I am trying to sense the power factor angle using microcontroller.

Now the mechanism that I have thought it that

1. Measure the zero crossing of voltage
2. When the voltage zero is sensed, start the timer of micrcontroller and then start sensing the zero of current.
3. But how to sense zero of currrent? By using a zero crossing current circui

My problem: I have made zero voltage circuit using transistor and opamps. The transistor is dependant upon the voltage applied between the emitter and base.When the voltage is zero, the transistor is off and the collector 5 V pulse is obtained accross collector and emitter.

But what for current? Is there any electronic device that is turned on/off by current ?

So I think the only solution is to convert the current into voltage and then sense the zero of voltage? Is it a viable solution?

I am trying to sense the power factor angle using microcontroller.

Now the mechanism that I have thought it that

1. Measure the zero crossing of voltage
2. When the voltage zero is sensed, start the timer of micrcontroller and then start sensing the zero of current.
3. But how to sense zero of currrent? By using a zero crossing current circuit

My problem: I have made zero voltage circuit using transistor and opamps. The transistor is dependant upon the voltage applied between the emitter and base.When the voltage is zero, the transistor is off and the collector 5 V pulse is obtained accross collector and emitter.

But what for current? Is there any electronic device that is turned on/off by current ?

So I think the only solution is to convert the current into voltage and then sense the zero of voltage. Is it a viable solution?