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2P4M is a solid state semiconductor device called Thyristor or SCR (Silicon Controlled Rectifier). The device is designed to have highly sensitive trigger levels and is suitable for applications where available gate currents are limited.

Pin Configuration

2P4M is a three pin device as shown in above 2P4M pin diagram and we will describe each of these pins below.






Connected to neutral



Low voltage trigger pulse is given to this pin to turning ON the SCR



Connected to Load


2P4M Features and Electrical characteristics

  • Easy installation by its miniature size and thin electrode leads
  • Low cost
  • Less holding current distribution provides free application design
  • Peak reverse blocking voltage: 500V
  • Peak on-state current: 2A
  • Peak gate current: 0.2A
  • Peak gate reverse voltage: 6V
  • Operating junction temperature range: -40ºC  to +125ºC 
  • Storage temperature range: -55ºC  to +150ºC 


2P4M Equivalent SCR

SN102, TIC206D, BT169, TYN604, 2N1596, 2N1595


2P4M SCR Overview

2P4M basically used in applications where gate currents are limited, such as capacitive discharge ignitions, motor control in kitchen aids and over voltage protection in low power supplies. The device is also used in low voltage AC rectifier and RMS voltage controller applications.


How to use 2P4M SCR

First understanding the working let us consider a simple application circuit for the device as shown in the circuit diagram below. Here V1 is the DC voltage source, a resistor type load is connected in series with SCR and Vg is the trigger voltage at the gate of the device. In addition Button 2 will be close by default and will break the circuit once it is pressed. Also in circuit, device Anode is connected to load and cathode is connected to second end of power source.

2P4M SCR Circuit Diagram

At initial state button B1 will be not pressed and in gate voltage absence SCR will be in non-conductive state. So under no trigger to the gate of the SCR (i.e. Vg =0V), the total drop appears across the device and we have Vload = 0V as shown in graph. This state continuous until a voltage pulse is give to the gate of the device and this is possible when button B1 is pressed.

So when B1 is pressed at a time T1 as shown in graph, SCR starts conducting and a voltage appears across the load as shown in the graph. Since the power supply is DC the SCR which was triggered ON will stay in conduction mode even after the gate voltage is removed after the device starts conducting. This is due to the characteristics of the device as a SCR.

Now for recovering the SCR to its high resistance state the current flow though the device must be brought to zero for fraction of second. Once the current is cutoff the charge stored in the device will dissipate and it will recover to its initial forward blocking state. And to drop the current through the loop to zero we will press button B2. Once this button is pressed the circuit loop will break and current flow though the device will become zero. As show in graph once the button B2 is pressed the voltage across the load will become zero due to the loop break and the device will start recovering.

After button B2 is released the device will again block the forward DC voltage and will wait for the gate pulse. So until the button B1 is pressed again the load voltage will be zero. As shown in graph the voltage appears across load after second trigger and this cycle of triggering and breaking continuous.

This way we have used the SCR as a switching device and in a similar way we can use in other applications.



  • Capacitor discharge ignitions
  • Motor control
  • Light dimmer
  • Battery charger
  • Various temperature control
  • AC rectifiers
  • RMS voltage switching
  • Power converters
  • Industrial switching



All measurements are in millimeter

2P4M SCR Dimensions

Component Datasheet