board

info

  • compare to - SSR-relay-dat

  • Thyristor-dat

  • Type: Bidirectional semiconductor device.

  • Structure: Basically two thyristors connected in inverse parallel in a single package.
  • Operation: Can conduct current in both directions when triggered.
  • Turn-off: Turns off when AC current crosses zero (natural commutation).
  • Applications:
    • AC light dimmers
    • Fan speed control
    • AC motor control
    • Household appliance controllers

3. Key Differences Table

Feature Thyristor (SCR) TRIAC
Current flow One direction (unidirectional) Both directions (bidirectional)
Main use DC or controlled rectifiers AC control (dimmers, speed control)
Gate trigger Positive gate with respect to cathode Triggerable in both polarities
Structure PNPN (4 layers) Two SCRs in anti-parallel
Commutation Needs forced or natural Natural at AC zero-crossing

✅ Summary:

  • Thyristor = one-way switch (mainly for DC).
  • TRIAC = two-way switch (mainly for AC).

TRIAC Comparison Table

Feature BT136 BTA12 BTA16 BT138
Maximum Voltage (V) 600V 600V 600V 600V
Maximum Current (A) 4A 12A 16A 12A
Gate Trigger Current (Igt) 5mA 35mA 35mA 10mA
Holding Current (Ih) 2mA 25mA 25mA 15mA
Thermal Resistance (Rth) 75°C/W 60°C/W 60°C/W 75°C/W
Package Type TO-220 TO-220 TO-220 TO-220
Applications General-purpose AC switching Light dimmers, motor controls High-power AC switching General-purpose AC switching

TRIAC

A TRIAC is a bidirectional, three-electrode AC switch that allows electrons to flow in either direction. It is the equivalent of two SCRs connected in a reverse-parallel arrangement with gates connected to each other. A TRIAC is triggered into conduction in both directions by a gate signal like that of an SCR.

SCR

SCR stands for Silicon Controlled Rectifier. It is a three-terminal device that is used to control the flow of current.

Demo

https://t.me/electrodragon3/198

intro of triac

A TRIAC (Triode for Alternating Current) is a type of semiconductor device that is used to control the flow of electrical power. It is essentially a bidirectional thyristor, meaning it can conduct current in both directions when triggered, making it particularly useful for AC (alternating current) applications.

Key points about TRIAC:

  • Bidirectional: Unlike a regular thyristor (which only conducts in one direction), a TRIAC can control the current flow in both directions, making it ideal for AC power control.
  • Triggering: It can be triggered by a small current applied to its gate, after which it allows current to pass through it until the current drops below a certain threshold.
  • Applications: TRIACs are commonly used in light dimmers, motor speed controls, and other devices where AC power needs to be modulated.

In short, a TRIAC is a specific type of thyristor designed for efficient AC power control.

TRIAC

https://www.electrodragon.com/w/Category:TRIAC

chips

demos

simple ON OFF drive - TRIAC-dat drive by BT136-dat == https://x.com/electric_4u/status/2054848924779962638

thyristor = 可控硅

It is a type of semiconductor device used for controlling high-power electric signals, often in switching applications.

MOC Triac driver

Feature MOC3020 (Random-Phase) MOC3021 (Random-Phase) MOC3063 (Zero-Cross)
Triggering Behavior Random-phase (non–zero–cross); triggers at any point in AC cycle Random-phase (non–zero–cross); similar to MOC3020 but optimized for lower LED drive Zero–cross; triggers only near the AC waveform’s zero point, reducing EMI and inrush current
LED Trigger Current Typical trigger current ~30 mA Typical trigger current ~15 mA Optimized for zero–cross operation (exact value varies per datasheet)
Applications Phase–control applications (lamp dimmers, motor controls) Phase–control applications where a lower drive current is desired AC switching (solid state relays, noise reduction, on/off control)
Isolation Voltage 5,000 Vrms 5,000 Vrms 5,000 Vrms
Off-State Output Voltage Minimum 400 V Minimum 400 V Minimum 400 V
dV/dt Rating Typically ≥1000 V/µs Typically ≥1000 V/µs May be optimized for zero–cross switching (check datasheet for specifics)

unsort

BT137-600E - 4Q Triac

ref

Table of Contents

https://www.electrodragon.com