Diac Db2 Datasheet Pdf 14 Top May 2026
This article provides a technical deep-dive into the Diac DB2 (Diode for Alternating Current), a critical bidirectional trigger device widely used in power control electronics. What is a Diac DB2?
A DIAC (Diode for Alternating Current) is a two-terminal semiconductor switch that remains in a high-resistance (off) state until a specific "breakover voltage" ( VBOcap V sub cap B cap O end-sub
) is reached. Once triggered, it switches to a low-resistance state, allowing current to flow in both directions. The DB2 is a specific variant, often manufactured by companies like STMicroelectronics and Shenzhen Luguang, known for its stability and precision in triggering thyristors. Top Technical Specifications (Datasheet Summary)
DB3 Diac Specifications and Datasheet | PDF | License - Scribd
This document provides specifications for DB3/DB4/DC34 trigger diodes, including: 1. They have low breakover currents of 32V, 34V, What Is DIAC? Symbol, Operating Principle, Structure, Uses
While "diac db2 datasheet pdf 14 top" appears to be a specific search string for a technical document, the DB2 DIAC is a fascinating piece of "legacy" semiconductor history that tells a broader story about how we learned to tame alternating current (AC). The "Ghost" in the Dimmer Switch
The DB2 is a member of the DIAC (Diode for Alternating Current) family, a bidirectional trigger diode that acts as a gatekeeper. For decades, these tiny, glass-encapsulated components have been the silent partners to TRIACs in almost every household light dimmer and ceiling fan speed controller.
The Problem: TRIACs, which handle the heavy lifting of AC power, are notoriously "finicky." They don't always trigger symmetrically on both halves of an AC cycle, leading to flickering lights or uneven motor speeds. diac db2 datasheet pdf 14 top
The DB2 Solution: The DIAC provides a sharp, consistent "kick" of current only after a specific threshold—the breakover voltage—is reached. By waiting until the voltage builds up to roughly 28–36V (depending on the specific model like the STMicroelectronics DB3), the DB2 ensures the TRIAC fires with perfect timing every single time. A Masterclass in Symmetrical Physics
What makes the DB2 "interesting" from an engineering perspective is its symmetry. Unlike a standard diode that works like a one-way valve, the DIAC is a multi-layer semiconductor (often 3 or 5 layers) that treats positive and negative voltage identically.
Negative Resistance: When it reaches its limit, the DB2 doesn't just "leak" current; it undergoes a rapid internal change where its resistance actually drops as current increases. This creates the high-speed pulse needed to wake up larger power components.
The "Legacy" Survival: Even in an era of microcontrollers and smart home tech, the DIAC remains relevant because it is incredibly cheap and electronically "quiet," producing less electromagnetic interference than many digital alternatives. Technical Snapshot (DB2/DB3 Series)
If you are looking for the "top" specifications typically found in a DB2 or DB3 datasheet, here is what defines them: Breakover Voltage ( VBOcap V sub cap B cap O end-sub ): Typically 32V (Range 28V–36V). Peak Pulse Current ( ITRMcap I sub cap T cap R cap M end-sub ): Can handle repetitive pulses up to 2A.
Package: Almost always a DO-35 (glass axial leaded) or SOT-23 (surface mount). Operating Temp: Rugged, typically rated from
Whether you're digging through old schematics or designing a simple AC controller, the DB2 represents a time when complex power problems were solved with elegant, solid-state physics rather than lines of code. Datasheet - DB3, DB4, SMDB3 - Diac - STMicroelectronics This article provides a technical deep-dive into the
The DB2 is a bidirectional DIAC (Diode for Alternating Current) trigger diode, primarily used in conjunction with TRIACs for simplified gate control in AC switching applications. While specific datasheets for the exact "DB2" designation can sometimes be less common than its closely related counterparts like the DB3 or DB4, it shares the same core functionality and physical characteristics. Key Technical Specifications
Based on standard industry DIAC datasheets from manufacturers like STMicroelectronics, here are the typical parameters for this series: Breakover Voltage ( VBOcap V sub cap B cap O end-sub
): Typically ranges between 28V and 36V for trigger-grade DIACs. Repetitive Peak On-State Current ( ITRMcap I sub cap T cap R cap M end-sub ): Up to 2.0 A ( Breakover Current ( IBOcap I sub cap B cap O end-sub ): Max 50 \mu A to 100 \mu A. Operating Temperature Range ( Tjcap T sub j ): -40∘Cnegative 40 raised to the composed with power cap C
+125∘Cpositive 125 raised to the composed with power cap C . Power Dissipation ( ): Approximately 150 mW at Rise Time ( ): Typically 1.5 \mu s to 2 \mu s. Physical & Mechanical Details Datasheet - DB3TG - Diac in DO-35 with tight VBO
The DB2 is a bidirectional trigger diode (DIAC) typically used to trigger TRIACs in AC control circuits, such as lamp dimmers and motor speed controls. While the exact "DB2" part number is less common than its successors, it is functionally equivalent to or replaced by more modern standard parts like the DB3 or SMDB3. Technical Specifications (Reference: DB3 Series)
Since DB2 is often grouped with the DB3/DB4 series in manufacturer catalogs, the following specifications are the standard for this class of bidirectional trigger diodes: DIAC DB2 DIODE Datasheet(PDF) - ALLDATASHEET.COM
DIAC DB2 DIODE Datasheet(PDF) - TMMDB3 - STMicroelectronics. ALLDATASHEET.COM DIAC / SIDAC, 28 V, 36 V - STMICROELECTRONICS | CPC UK Go to Datasheet4U or Alldatasheet Search for: "DB2
I understand you're looking for a review of a document titled "DIAC DB2 Datasheet PDF" (possibly with "14 top" meaning a top-14 list or a specific section). However, I don't have direct access to external PDFs or a specific file named exactly like that in my training data.
To help you effectively, I can offer the following:
6. How to Find the Official Datasheet PDF
To obtain the official manufacturer datasheet:
- Go to Datasheet4U or Alldatasheet
- Search for: "DB2 DIAC datasheet"
- Preferred manufacturer part numbers:
ST DB2(STMicroelectronics)Diotec DB2NTE5325(NTE Electronics – equivalent)
- Download the PDF – it will show the V_BO = 28-36V and no 14V variant.
How to Download the DB2 Datasheet PDF
To obtain the official diac db2 datasheet pdf, follow these steps:
- Go to Octopart.com or Mouser.com.
- Search for "DB2 DIAC".
- Click on the component listing and find "Datasheet" under technical documents.
- Alternatively, search on ST.com for "DB3" (identical electrical specs).
- Save the PDF for offline access – it contains all the 14 top parameters mentioned above.
Pro Tip: If the search returns zero results for DB2, use "DB3" as STMicroelectronics merged DB2 into the DB3 family. The technical datasheet PDF is identical.
8. Example electrical schematic (conceptual)
- AC supply → series resistor → potentiometer → DIAC → gate of TRIAC → load (lamp/motor).
- DIAC remains off until capacitor charges to VBO, then conducts to fire TRIAC.
Typical specs in a DIAC DB2 datasheet:
- Breakover voltage ( V_BO ): typically 32–40 V
- Breakover current ( I_BO )
- Peak pulse current ( I_PM )
- Switching characteristics
- Temperature range
7. Typical Application Circuit (TRIAC Triggering)
AC Mains
|
LOAD
|
/ \ DIAC DB2
/ \ |
| |--------●----- G
| | |
----- TRIAC
| (e.g., BT136)
C R |
(R/C snubber) A2
| |
Neutral -----------
- Function: DIAC provides a sharp trigger pulse to TRIAC gate once the capacitor voltage reaches V_BO (≈32V).
- Result: Phase control for dimming/motor speed.
1. Breakover Voltage (VBO) – #1 on the List
The DB2 has a nominal VBO of 32V (typically between 30V and 34V). This symmetry is crucial for AC applications, ensuring the DIAC triggers at the same voltage magnitude on both half-cycles. A poorly matched DIAC introduces even-order harmonics and flicker in dimmers.
4. On-State Current (ITM) – #5
While the DB2 is a small signal device, it can handle repetitive peak currents of 2A for short durations (10 ms at 50/60 Hz). This is sufficient to trigger most TRIACs in the Z0103, BT136, or BTA series.
