For a SCR the maximum rms on-state current is 35 A. If the SCR is used in a resistive circuit for a rectangular wave with conduction angle of 90°. Calculate the average & rms currents respectively.

To calculate the average and rms currents for an SCR used in a resistive circuit with a rectangular wave and a conduction angle of 90°, we can use the following formulas:

1. Average Current (I_avg):

– For a rectangular waveform, the average current can be calculated with the formula:

[

I_{avg} = frac{I_{max} cdot theta}{2pi}

]

where ( I_{max} ) is the maximum current (which is also the rms current in this case) and ( theta ) is the conduction angle in radians.

– Conduction angle ( theta = 90^circ = frac{pi}{2} ) radians.

– Therefore:

[

I_{avg} = frac{35 A cdot frac{pi}{2}}{2pi} = frac{35 A}{4} = 8.75 A

]

2. RMS Current (I_rms):

– For a rectangular waveform with a conduction angle of 90°, the rms value can be calculated with the formula:

[

I_{rms} = I_{max} cdot sqrt{frac{theta}{2pi}}

]

– Therefore:

[

I_{rms} = 35 A cdot sqrt{frac{frac{pi