## Voltage across first thyristor in series-connected thyristors Solution

STEP 0: Pre-Calculation Summary
Formula Used
Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string
VD1 = (Vs+(ns-1)*R*ΔID)/ns
This formula uses 5 Variables
Variables Used
Voltage across thyristor 1 in thyristor string - (Measured in Volt) - Voltage across thyristor 1 in thyristor string is the voltage across the first thyristor of the series combination.
Resultant series voltage of thyristor string - (Measured in Volt) - Resultant series voltage of thyristor string is the resultant voltage of the series combination of ns number of thyristors.
Number of thyristors in series thyristor string - Number of thyristors in series thyristor string is the quantity of thyristors in the series combination.
Resistance - (Measured in Ohm) - Resistance is a measure of the opposition to current flow in an electrical circuit. Its S.I unit is ohm.
Off state current spread of thyristor string - (Measured in Ampere) - Off state current spread of thyristor string is the difference between the two currents across adjacent thyristors in the string.
STEP 1: Convert Input(s) to Base Unit
Resultant series voltage of thyristor string: 20 Volt --> 20 Volt No Conversion Required
Number of thyristors in series thyristor string: 3 --> No Conversion Required
Resistance: 10 Ohm --> 10 Ohm No Conversion Required
Off state current spread of thyristor string: 5 Ampere --> 5 Ampere No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
VD1 = (Vs+(ns-1)*R*ΔID)/ns --> (20+(3-1)*10*5)/3
Evaluating ... ...
VD1 = 40
STEP 3: Convert Result to Output's Unit
40 Volt --> No Conversion Required
40 Volt <-- Voltage across thyristor 1 in thyristor string
(Calculation completed in 00.031 seconds)
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## < 10+ Thyristors Calculators

Excess work due to thyristor 1 in chopper circuit
Excess energy in chopper circuit = 0.5*Reverse di/dt limiting inductance*((Load current of chopper circuit+(Reverse Recovery Time*Commutation capacitor voltage)/Reverse di/dt limiting inductance)-(Load current of chopper circuit^2)) Go
Worst case steady state voltage across first thyristor in series connected thyristors
Worst case steady state voltage of thyristor 1 = ((Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string))/Number of thyristors in series thyristor string Go
Voltage across first thyristor in series-connected thyristors
Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string Go
Resultant series voltage of series connected thyristor string
Resultant series voltage of thyristor string = Number of thyristors in series thyristor string*Voltage across thyristor 1 in thyristor string-(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string Go
Maximum Thyristor gate voltage for resistance firing circuit
Maximum gate voltage = Maximum AC input voltage*(Stabilizing Resistance/(Stabilizing Resistance+Variable Resistance+Resistance)) Go
Derating factor of series connected thyristor string
Derating factor of thyristor string = 1-(Resultant series voltage of thyristor string/(Number of thyristors in series thyristor string*Worst case steady state voltage of thyristor 1)) Go
Power dissipated by heat in SCR
Power dissipated by heat in SCR = (SCR junction temperature-SCR ambient temperature)/Thermal resistance of SCR Go
Thermal resistance of SCR
Thermal resistance of SCR = (SCR junction temperature-SCR ambient temperature)/Power dissipated by heat in SCR Go
Leakage current of the collector-base junction
Collector to base leakage current = Collector current-(Common-base current gain.*Emitter current) Go
Discharging current of dv/dt protection thyristor circuits
Discharging current of thyristor circuit = Input voltage/((Resistance 1+Resistance 2)) Go

## Voltage across first thyristor in series-connected thyristors Formula

Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string
VD1 = (Vs+(ns-1)*R*ΔID)/ns

## Why is string connection of thyristors needed?

Thyristors are needed in a string connection to meet the high voltage requirement. Though the rating of individual SCR has greatly increased and SCR with voltage and current rating of 10 kV & 3 kA are readily available, but in the industrial application the voltage and current requirement may be more.

## How to Calculate Voltage across first thyristor in series-connected thyristors?

Voltage across first thyristor in series-connected thyristors calculator uses Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string to calculate the Voltage across thyristor 1 in thyristor string, The Voltage across first thyristor in series-connected thyristors formula is the voltage across the first thyristor of the series combination of the thyristors. Voltage across thyristor 1 in thyristor string is denoted by VD1 symbol.

How to calculate Voltage across first thyristor in series-connected thyristors using this online calculator? To use this online calculator for Voltage across first thyristor in series-connected thyristors, enter Resultant series voltage of thyristor string (Vs), Number of thyristors in series thyristor string (ns), Resistance (R) & Off state current spread of thyristor string (ΔID) and hit the calculate button. Here is how the Voltage across first thyristor in series-connected thyristors calculation can be explained with given input values -> 40 = (20+(3-1)*10*5)/3.

### FAQ

What is Voltage across first thyristor in series-connected thyristors?
The Voltage across first thyristor in series-connected thyristors formula is the voltage across the first thyristor of the series combination of the thyristors and is represented as VD1 = (Vs+(ns-1)*R*ΔID)/ns or Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string. Resultant series voltage of thyristor string is the resultant voltage of the series combination of ns number of thyristors, Number of thyristors in series thyristor string is the quantity of thyristors in the series combination, Resistance is a measure of the opposition to current flow in an electrical circuit. Its S.I unit is ohm & Off state current spread of thyristor string is the difference between the two currents across adjacent thyristors in the string.
How to calculate Voltage across first thyristor in series-connected thyristors?
The Voltage across first thyristor in series-connected thyristors formula is the voltage across the first thyristor of the series combination of the thyristors is calculated using Voltage across thyristor 1 in thyristor string = (Resultant series voltage of thyristor string+(Number of thyristors in series thyristor string-1)*Resistance*Off state current spread of thyristor string)/Number of thyristors in series thyristor string. To calculate Voltage across first thyristor in series-connected thyristors, you need Resultant series voltage of thyristor string (Vs), Number of thyristors in series thyristor string (ns), Resistance (R) & Off state current spread of thyristor string (ΔID). With our tool, you need to enter the respective value for Resultant series voltage of thyristor string, Number of thyristors in series thyristor string, Resistance & Off state current spread of thyristor string and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
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