BT136 Transistor BT136-600E BT136 600E TRIAC 4A 600V 3 Pin Leads TO-220 Package 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.
A range of TRIACs (Triodes for Alternating Current is also known as Bidirectional Thyristors).
They are used in AC switching and control applications with current ratings from under 1A to 40A rms.
A TRIAC makes a convenient switch for alternating current circuit.
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.
Specification
The rated average on state current: 4 A
Maximum gate trigger current: 10 mA
Maximum holding current: 10 mA
Surge current rating: 27 A
The repetitive peak of state current: 0.5 mA
Maximum gate trigger voltage: 1.5 Volts
Repetitive peak reverse voltage: 600 Volts
Repetitive peak forward blocking voltage: 600 Volts
The peak on state voltage: 1.7 Volts
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.
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.
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
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.