Thyristor Firing Angle for RC Firing Circuit Calculator

✖Gate Threshold Voltage is the minimum voltage required at the gate terminal of an SCR to turn it on.ⓘ Gate Threshold Voltage [V_th]			+10% -10%
✖Stablizing Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit which is used to stablize.ⓘ Stablizing Resistance [R_stb]			+10% -10%
✖Variable Resistance is variable resistance whose value can be varied to prevent the relay from operating due to saturation of the current during transistors and thyristor start-up.ⓘ Variable Resistance [R_var]			+10% -10%
✖Thyristor Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit.ⓘ Thyristor Resistance [R_thy]			+10% -10%
✖Peak Input Voltage is the peak of the alternating voltage provided at the input of any electrical circuit.ⓘ Peak Input Voltage [V_max]			+10% -10%

✖Firing angle is the angle in the AC cycle at which the thyristor starts conducting at the application of positive voltage to gate.ⓘ Thyristor Firing Angle for RC Firing Circuit [∠α]

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Formula

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Thyristor Firing Angle for RC Firing Circuit

Formula

`"∠α" = asin("V"_{"th"}*(("R"_{"stb"}+"R"_{"var"}+"R"_{"thy"})/("V"_{"max"}*"R"_{"stb"})))`

Example

`"1.214859°"=asin("1.7V"*(("32Ω"+"5.8Ω"+"50Ω")/("220V"*"32Ω")))`

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Thyristor Firing Angle for RC Firing Circuit Solution

STEP 0: Pre-Calculation Summary

Formula Used

Firing Angle = asin(Gate Threshold Voltage*((Stablizing Resistance+Variable Resistance+Thyristor Resistance)/(Peak Input Voltage*Stablizing Resistance)))
∠α = asin(V_th*((R_stb+R_var+R_thy)/(V_max*R_stb)))
This formula uses 2 Functions, 6 Variables

Functions Used

sin - Sine is a trigonometric function that describes the ratio of the length of the opposite side of a right triangle to the length of the hypotenuse., sin(Angle)
asin - The inverse sine function, is a trigonometric function that takes a ratio of two sides of a right triangle and outputs the angle opposite the side with the given ratio., asin(Number)

Variables Used

Firing Angle - (Measured in Radian) - Firing angle is the angle in the AC cycle at which the thyristor starts conducting at the application of positive voltage to gate.
Gate Threshold Voltage - (Measured in Volt) - Gate Threshold Voltage is the minimum voltage required at the gate terminal of an SCR to turn it on.
Stablizing Resistance - (Measured in Ohm) - Stablizing Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit which is used to stablize.
Variable Resistance - (Measured in Ohm) - Variable Resistance is variable resistance whose value can be varied to prevent the relay from operating due to saturation of the current during transistors and thyristor start-up.
Thyristor Resistance - (Measured in Ohm) - Thyristor Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit.
Peak Input Voltage - (Measured in Volt) - Peak Input Voltage is the peak of the alternating voltage provided at the input of any electrical circuit.

STEP 1: Convert Input(s) to Base Unit

Gate Threshold Voltage: 1.7 Volt --> 1.7 Volt No Conversion Required
Stablizing Resistance: 32 Ohm --> 32 Ohm No Conversion Required
Variable Resistance: 5.8 Ohm --> 5.8 Ohm No Conversion Required
Thyristor Resistance: 50 Ohm --> 50 Ohm No Conversion Required
Peak Input Voltage: 220 Volt --> 220 Volt No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

∠α = asin(V_th*((R_stb+R_var+R_thy)/(V_max*R_stb))) --> asin(1.7*((32+5.8+50)/(220*32)))

Evaluating ... ...

∠α = 0.0212032932712534

STEP 3: Convert Result to Output's Unit

0.0212032932712534 Radian -->1.21485921622119 Degree (Check conversion here)

FINAL ANSWER

1.21485921622119 ≈ 1.214859 Degree <-- Firing Angle

(Calculation completed in 00.004 seconds)

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< 10+ SCR Firing Circuit Calculators

Thyristor Firing Angle for RC Firing Circuit

Go Firing Angle = asin(Gate Threshold Voltage*((Stablizing Resistance+Variable Resistance+Thyristor Resistance)/(Peak Input Voltage*Stablizing Resistance)))

Peak Thyristor Gate Voltage for Resistance Firing Circuit

Go Maximum Gate Voltage = (Peak Input Voltage*Stablizing Resistance)/(Variable Resistance+Thyristor Resistance+Stablizing Resistance)

Firing Angle of UJT as Oscillator Thyristor Firing Circuit

Go Firing Angle = Angular Frequency*Stablizing Resistance*Capacitance*ln(1/(1-Intrinsic Stand-off Ratio))

Time Period for UJT as Oscillator Thyristor Firing Circuit

Go Time Period of UJT as Oscillator = Stablizing Resistance*Capacitance*ln(1/(1-Intrinsic Stand-off Ratio))

Peak Thyristor Gate Voltage for RC Firing Circuit

Go Maximum Gate Voltage = Gate Threshold Voltage/(sin(Angular Frequency*Time Period of Progressive Wave))

Emitter Current for UJT based Thyristor Firing Circuit

Go Emitter Current = (Emitter Voltage-Diode Voltage)/(Emitter Resistance Base 1+Emitter Resistance)

Frequency of UJT as Oscillator Thyristor Firing Circuit

Go Frequency = 1/(Stablizing Resistance*Capacitance*ln(1/(1-Intrinsic Stand-off Ratio)))

Intrinsic Stand-off Ratio for UJT based Thyristor Firing Circuit

Go Intrinsic Stand-off Ratio = Emitter Resistance Base 1/(Emitter Resistance Base 1+Emitter Resistance Base 2)

Discharging Current of dv-dt Protection Thyristor Circuits

Go Discharging Current = Input Voltage/((Resistance 1+Resistance 2))

Emitter Voltage to Turn On UJT based Thyristor Firing Circuit

Go Emitter Voltage = Emitter Resistance Base 1 Voltage+Diode Voltage

Thyristor Firing Angle for RC Firing Circuit Formula

What is an RC firing circuit?

RC triggering circuit consisting of two diodes with an RC network connected to turn the SCR. By varying the variable resistance, triggering or firing angle is controlled in a full positive half cycle of the input signal. During the negative half cycle of the input signal, capacitor charges with lower plate positive through diode D2 up to the maximum supply voltage Vmax. This voltage remains at -Vmax across the capacitor till supply voltage attains zero crossing. During the positive half cycle of the input, the SCR becomes forward biased and the capacitor starts charging through variable resistance to the triggering voltage value of the SCR. When the capacitor charging voltage is equal to the gate trigger voltage, SCR is turned ON and the capacitor holds a small voltage. Therefore the capacitor voltage is helpful for triggering the SCR even after 90 degrees of the input waveform.

How to Calculate Thyristor Firing Angle for RC Firing Circuit?

Thyristor Firing Angle for RC Firing Circuit calculator uses Firing Angle = asin(Gate Threshold Voltage*((Stablizing Resistance+Variable Resistance+Thyristor Resistance)/(Peak Input Voltage*Stablizing Resistance))) to calculate the Firing Angle, The Thyristor firing angle for RC firing circuit formula is defined as the firing angle at which the thyristor starts conducting. Firing Angle is denoted by ∠α symbol.

How to calculate Thyristor Firing Angle for RC Firing Circuit using this online calculator? To use this online calculator for Thyristor Firing Angle for RC Firing Circuit, enter Gate Threshold Voltage (V_th), Stablizing Resistance (R_stb), Variable Resistance (R_var), Thyristor Resistance (R_thy) & Peak Input Voltage (V_max) and hit the calculate button. Here is how the Thyristor Firing Angle for RC Firing Circuit calculation can be explained with given input values -> 69.60631 = asin(1.7*((32+5.8+50)/(220*32))).

FAQ

What is Thyristor Firing Angle for RC Firing Circuit?

The Thyristor firing angle for RC firing circuit formula is defined as the firing angle at which the thyristor starts conducting and is represented as ∠α = asin(V_th*((R_stb+R_var+R_thy)/(V_max*R_stb))) or Firing Angle = asin(Gate Threshold Voltage*((Stablizing Resistance+Variable Resistance+Thyristor Resistance)/(Peak Input Voltage*Stablizing Resistance))). Gate Threshold Voltage is the minimum voltage required at the gate terminal of an SCR to turn it on, Stablizing Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit which is used to stablize, Variable Resistance is variable resistance whose value can be varied to prevent the relay from operating due to saturation of the current during transistors and thyristor start-up, Thyristor Resistance is defined as the opposition faced by the flow of current through a thyristor based circuit & Peak Input Voltage is the peak of the alternating voltage provided at the input of any electrical circuit.

How to calculate Thyristor Firing Angle for RC Firing Circuit?

The Thyristor firing angle for RC firing circuit formula is defined as the firing angle at which the thyristor starts conducting is calculated using Firing Angle = asin(Gate Threshold Voltage*((Stablizing Resistance+Variable Resistance+Thyristor Resistance)/(Peak Input Voltage*Stablizing Resistance))). To calculate Thyristor Firing Angle for RC Firing Circuit, you need Gate Threshold Voltage (V_th), Stablizing Resistance (R_stb), Variable Resistance (R_var), Thyristor Resistance (R_thy) & Peak Input Voltage (V_max). With our tool, you need to enter the respective value for Gate Threshold Voltage, Stablizing Resistance, Variable Resistance, Thyristor Resistance & Peak Input Voltage and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Firing Angle?

In this formula, Firing Angle uses Gate Threshold Voltage, Stablizing Resistance, Variable Resistance, Thyristor Resistance & Peak Input Voltage. We can use 1 other way(s) to calculate the same, which is/are as follows -

Firing Angle = Angular Frequency*Stablizing Resistance*Capacitance*ln(1/(1-Intrinsic Stand-off Ratio))

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