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BT136 Triac: Datasheet, Pinout, Equivalent [FAQ]

  • Contents

BT136 is a type of electronic components, which is a triac.

The thyristor is also the abbreviation of the thyristor rectifier element. It is a high-power semiconductor device with a four-layer structure with three PN junctions, which is generally formed by reversely connecting two thyristors. Its function is not only to rectify, but also to be used as a non-contact switch to quickly turn on or off the circuit, realize the inversion of the direct current into the alternating current, the alternating current of one frequency into the alternating current of another frequency, and so on.

The thyristor, like other semiconductor devices, has the advantages of small size, high efficiency, good stability, and reliable operation. With its emergence, semiconductor technology has moved from the weak current field to the strong current field, and has become a component used in industries, agriculture, transportation, military scientific research, as well as commercial and civilian electrical appliances.

  • Name: BT136
  • Features: High breakdown voltage, large output current
  • Description: Plastic single-ended package; heatsink mounted; 1 mounting hole; 3-lead TO-220AB
  • Package: TO-220

Catalog

BT136 Pinout

BT136 Features

PT136 Applications

BT136 Advantage

TRIAC Application Tips

BT136 Equivalents

How to use BT136

BT136 Package

Component Datasheet

FAQ


BT136 Pinout

BT136 Pinout

Pin Number

Symbol

Description

1

T1

Main Terminal  1: Connected to Phase or neutral of AC mains

2

T2

Main Terminal 2:Connected to Phase or neutral of AC mains

3

G

Gate :Used to trigger the SCR.


BT136 Features

Direct triggering from low power drivers and logic ICs

• High blocking voltage capability

• Low holding current for low current loads and lowest EMI at commutation

• Planar passivated for voltage ruggedness and reliability

• Sensitive gate

• Triggering in all four quadrants


PT136 Applications

• General purpose motor control

• General purpose switching


BT136 Advantage

BT136 IC

BT136 TRIAC IC

The BT136 is TRIAC with 4A maximum terminal current. The gate threshold voltage of the BT136 is also very less so can be driven by digital circuits.

Since TRIACs are bi-directional switching devices they are commonly used for switching AC applications. So if you looking to switch of control (dim, speed control) an AC load which consumes less than 6A with a digital device like microcontroller or microprocessor then BT136 might be the right for you.

Planar passivated sensitive gate four quadrant triac in a SOT78 plastic package intended for use in general purpose bidirectional switching and phase control applications. This sensitive gate "series E" triac is intended to be interfaced directly to microcontrollers, logic integrated circuits and other low power gate trigger circuits.


TRIAC Application Tips

Since TRIACS deal with AC voltages, the circuit involving them has to be designed properly to aboid problem some tips are shared below

All TRIAC circuits suffer from an effect called Rate Effect. This occurs when the TRIAC is switching frequently and a sudden high voltage occurs at either main terminal of the TRIAC and damages the TRIAC itself. It can be avoided by using a snubber circuit.

Similarly there is another effect called backlash effect. This occurs due to the capacitance that gets accumulated between the two terminals of the MT1 and MT2 of the TRIAC. Due to this the TRIAC will not turn on even if the gate voltage is applied. This problem can be solved by providing a resistance in series for the capacitance to discharge.

When controlling the output AC voltage for dimmer or speed control applications a Zero crossing method is always recommended to be used.

In switching circuits the TRIAC is easily subjected to harmonics and EMI interference hence should be isolated from other digital electronics.

There is chance of backward current when the TRIAC is switching inductive loads, so an alternate discharge path has to be provided for the load to drain the inrush current.


BT136 Equivalents

BTA08-600B


How to use BT136

There are many different ways to use a TRIAC, since the device is bi-directional the TRIAC gate can be trigger with either positive voltage or negative voltage. So this allows the TIRAC to be operated in four different modes. You can read this article if you want to know more about the switching modes. A simple TRIAC switching circuit is shown below.

How to use BT136?

In this circuit the TRIAC can be turned using the switch, when the switch is pressed the TRIAC closes the connection for the AC bulb though the AC mains. For this to happen, the gate pin of the TRIAC should receive a voltage greater than the threshold gate voltage and should also get a current that is greater than gate trigger current. This will make the TRIAC turn on.

Since the TRIAC and SCR share most of the same characteristics, just like SCR the TRIAC will also not turn off when the gate voltage is removed. We need special type of circuit called commutation circuit to turn of the SCR again. This commutation is normally done by reducing the load current (forced commutation) less than the holding current. To put it simple the TRIAC will remain turned on only till the load current is greater than the holding current of the TRIAC.

Note: Commutation is not required in AC switching circuits because the TRIAC will not latch in on state since the AC voltage reaches zero for every half cycle.

Other than controlling through switch the BT136 can also be controlled through a microcontroller or a microprocessor. To do this we need an Opto-isolator like MOC3021 to isolate the AC circuit form Digital electronics. This way the Load can not only be switched but also the output coltage can be controlled by using PWM signals for fast switching.


BT136 Package

Package Name: TO-220AB

Package Description: plastic single-ended package; heatsink mounted; 1 mounting hole; 3-lead TO-220AB

Package Version: SOT78

Package Outline:

PT136 Package


Component Datasheet

BT136-600E Datasheet


FAQ

  • What is BT136?

The BT136 is TRIAC with 4A maximum terminal current. The gate threshold voltage of the BT136 is also very less so can be driven by digital circuits. Since TRIACs are bi-directional switching devices they are commonly used for switching AC applications.

  • What does a triac do?

Triacs are electronic components that are widely used in AC power control applications. They are able to switch high voltages and high levels of current, and over both parts of an AC waveform. This makes triac circuits ideal for use in a variety of applications where power switching is needed.

 

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