2N1595 Thyristor : Pin Configuration & Its Applications

A 2N1595 thyristor is a three-terminal and four-layered semiconductor device where the terminals are the anode, cathode, and gate & layers are P-N-N-P. Generally, a thyristor works like a switch to control the power. This is a lightweight and small component and provides sufficient protection to different circuits which operate with large currents & voltages upto 4500 A & 6000 V.

Generally, the thyristor is also called Silicon Controlled Rectifier or SCR. So, a 2N1595 thyristor is a low-current and industrial-type component accessible in a three-lead package and used in printed-circuit applications. These thyristors have many benefits like maintenance cost is low, less weight, small, operates under the correct conditions and without developing a fault in the circuit, it works for a long time. This article discusses an overview of a 2N1595 Thyristor, pin configuration, features, specifications circuit working, and its applications.

What is 2N1595 Thyristor?

2N1595 thyristor is a silicon-based solid-state semiconductor component which is also known as Silicon Controlled Rectifier or SCR. It is available in a 3-lead package with low current & industrial-type, so used in printed-circuit-based applications.

Generally, this thyristor is used in low voltage AC rectifying, RMS voltage controller & AC rectifier-based applications. The current handling capacity of this thyristor is 1.6 A at 100°C junction temperature.

Pin Configuration:

The pin configuration of a 2N1595 Thyristor includes three terminals where each terminal and its functionality are shown below.

• Pin1 (Cathode): This terminal is connected to neutral
• Pin2 (Gate): Low voltage based trigger pulse is given to this pin
• Pin3 (Anode): It is connected to Load

Features & Specifications:

The features and specifications of 2N1595 Thyristor include the following.

• Reliability is high
• Turn-On time is 0.8µS
• Turn-Off Time is 10µS
• Available as non-RoHS
• Maximum blocking voltage in reverse is 50V
• The body holder is suitable for fixing the heat sink
• The maximum surge current is 15A
• The maximum gate current is 0.1A
• The maximum gate voltage is 10V
• Storage temperature ranges from -65ºC to +150ºC
• Operating temperature ranges from -65ºC to +125ºC
• Maximum repetitive current handling capacity is 1.6 A at125°C
• SCR type
• Maximum gate power or PGM is 0.1 W
• The maximum on-state current of RMS is (IT(RMS)) is 1.6 A
• The available package is TO 205AD
• Maximum repetitive peak and off-state voltage (VDRM): 50 V
• Holding current or IH is 5 mA
• The maximum on-state voltage drop or VTM is 1.1 V
• Triggering gate current or IGT is 2 mA
• Triggering gate voltage or VGT is 0.7 V
• The maximum forward blocking voltage or VDRM is 50V
• Maximum reverse blocking current or IRRM is 1mA
• Trigger current for gate terminal or IGT is typically 2mA & Max 10mA
• Trigger voltage of gate terminal or VGT is typically 0.7 and maximum of 3V
• Holding current or IH is 5mA

Equivalent 2N1595 Thyristors are 2N1596, 2N1598, 2N1597 & 2N1599. Alternate 2N1595 Thyristor is 2N2323.

How to use 2N1595 Thyristor/Circuit Diagram

The over-voltage protection using a 5V regulated power supply circuit diagram is shown below. The required components to build this circuit mainly includes different electronic components like 1N4001 diodes – 4, 1A fuse, 2N1595 thyristor, 7805 voltage regulator IC, 2N1595 Thyristor 1N3997 Zener diode for protecting the circuit from overvoltage.

Fuse is a safety device, used to give protection from extreme current, however, they cannot give protection from transients & high voltage short duration spikes on the power supply lines. So the following circuit uses the “crowbar” technique to provide quick protection from transient voltage spikes for protecting sensitive components within the circuit.

The following 5V regulated power supply circuit includes over-voltage protection. The 5V RPS or regulated power supply is an a74LS series-based chip that has to be accurate & tolerant of voltage transients. Once a voltage spike occurs within the circuit then the IC can be damaged.

In this circuit, a Fuse is used as a protecting device. Once the rating of current is increased then a fuse will blow but uses 100 milliseconds to react. This circuit responds within a few milliseconds and is activated once the output voltage increases the more zen diode’s limit. The process used in this circuit is a crowbar, wherever an SCR is used & short circuits the supply to make the fuse blow. As compared to a normal fuse, this fuse gives high protection

Once the output voltage is increased to 6V, then the Zener diode will perform to switch ON the thyristor in a few milliseconds. Thus, the output voltage is decreased to zero volts then sensitive logic integrated circuits will be protected automatically.

The fuse in the above circuit takes a few milliseconds to blow. The input DC to the regulator must be high as compared to the voltage regulator. For a 5V regulator power supply (RPS), it is recommended to utilize a transformer including secondary voltage from 8V to 10V AC.

Advantages & Disadvantages

The advantages of thyristors are;

• It is simple to turn on and control
• Controls AC power
• Less cost
• It can switch high current & high device
• It handles with large current, voltage & power
• The SCR triggering is very simple

The disadvantages of thyristors are;

• Switching speed is low
• It cannot be turned off easily
• Gate terminal current cannot be negative
• Every cycle in AC circuits need to switch ON

Where to use 2N1595 Thyristor/Applications

The applications of 2N1595 Thyristor include the following.

• Switch Mode Power Supply
• Power regulators
• AC rectifiers
• Industrial switching
• RMS voltage switching
• Power converters
• Low-voltage based AC rectifying applications
• RMS voltage controller-based applications.
• A thyristor is very attractive like a rectifier as it can switch quickly from a conducting
• These are used in a variety of electric circuits which range from simple burglar alarms to power transmission lines.
• These are used in different electronic and electrical circuits like relay-replacement, power-switching, chopper, inverter, light-dimming, low-cost timer speed-control, oscillator, level-detector, logic, phase-control, etc.

Please refer to this link to know more about 2N1595 Thyristor Datasheet.

Thus, the 2N1595 SCR can be replaced through the 2N2322 based on the operating voltage and circuit requirement. The main difference between these two is, the 2N1595 thyristor has a high repetitive peak reverse voltage like 50V while the 2N2322 has a low repetitive peak reverse voltage like 25V. Thus, we can change the 2N1595 thyristor with the 2N2323 because they are available with the same metal package as TO-39 & also they have similar characteristics. Here is a question for you, what is the main function of a Thyristor?