Electrical Concepts

Series connection of SCR is required where we want to meet the increased voltage requirement by using various SCRs.  Let us make it easier to understand. Suppose the SCR available with us is having a voltage rating of 600 V but the voltage rating required for our application is 2400 V. In this case, if … Read more

String Efficiency of SCR: String Efficiency of SCR is the degree of capacity utilization of individual SCRs in a string of series / parallel connected SCRs. String efficiency is always less than 1. Series or parallel connection of SCR is required to meet the higher voltage / current requirement in industrial application. Though the rating … Read more

Snubber Circuit is a circuit consisting of series combination of resistance and capacitance in parallel with SCR. This article describes the purpose, design and working principle of Snubber Circuit in detail. Purpose of Snubber Circuit The main purpose of Snubber Circuit is to prevent the unwanted triggering of SCR or thyristor due to high rate … Read more

Switching characteristics of SCR is the time variation of voltage across its anode and cathode terminals and the current through it during its turn on and turn off process. This means, there will be two types of characteristics: One during turn on process and other during turn off process of SCR. It is also known … Read more

di/dt protection is required to protect thyristor or SCR from the formation of local hot spot due to high value of rate of change of anode current i.e. di/dt near the gate to cathode junction during its turn on process. When a thyristor or SCR is forward biased and is turned on by gate pulse, … Read more

The main difference between latching and holding current of SCR is that latching current is related with turn on process while holding current is related with turn off process of SCR. Latching current of forward biased SCR is the minimum current which anode current must attain to continue to remain in forward conduction mode even … Read more

SCR Turn on methods are the techniques to bring an SCR in forward conduction mode from forward blocking mode. An SCR in forward conduction mode is characterized by low impedance, low voltage drop across anode & cathode and high anode current. The value of anode current is determined by the load. Thus it allows for … Read more

Definition of V-I Characteristics of SCR A V-I Characteristic of SCR (Silicon Controlled Rectifier) is the voltage current characteristics. The current through the SCR varies as the Anode to Cathode terminal voltage and Gate to Cathode terminal voltage is varied. The graphical representation of current through the SCR and voltage across the anode to cathode … Read more