BT151X-800R,127
WeEn Semiconductors
SCR 800V 12A TO220-3
MOQ 1 · Tube · RoHS · EIA-481 · DAP/DDP · T/T
Technical specifications
| Parameter / Attribute | Specification / Value |
|---|---|
| SCR type | Standard Recovery |
| Mounting | Through Hole |
| Voltage - off state | 800 V |
| Voltage - on state (Vtm) | 1.75 V |
| Voltage - gate trigger (Vgt) | 1.5 V |
| Current - hold (Ih) | 20 mA |
| Current - off state | 500 µA |
| Current - gate trigger (Igt) | 15 mA |
| Current - on state (It (AV)) | 7.5 A |
| Current - on state (It (RMS)) | 12 A |
| Current - non rep. surge 50, 60Hz | 120A, 132A |
| Operating temperature | -40°C~125°C |
| Package | Tube |
| Case | TO-220-3 Full Pack, Isolated Tab |
Need Stock or a Drop-in Second-Source for BT151X-800R,127?
Package: TO-220AB (SOT78) · Pin-compatible replacements with immediate Shenzhen spot stock
The BT151 is the 12A workhorse SCR of battery chargers, motor speed controllers, welder crowbars and heating control - a TO-220AB thyristor whose orderable number carries both its blocking voltage (500/600/650/800V suffixes) and hides its gate sensitivity in the grade. Its family ladder is well stocked and genuinely interchangeable with reading: BT152 as the 20A rung, the ST-named TYN612/TYN616 as direct counterparts, TYN812 for the 800V class. Two traps surround it: the gate trigger current differs across the ladder (a swap that will not latch on cold boards), and the name sits one digit from the BT136/BTA16 triac family - a different device in a different circuit, sharing only a drawer.
Verified Pin-Compatible Replacements (3 verified alternatives)
The 20A Rung of the Same Ladder
Shenzhen Spot Stock (24-48h Dispatch)
The higher-current member: 16-20A class where the BT151 carries 12A RMS, same 600V blocking and the same TO-220AB body - the standard margin upgrade for a charger or crowbar that keeps dying at the die.
Same blocking ladder (600/800V variants); the surge rating scales with the die size.
The ST-Named Direct Counterpart
Shenzhen Spot Stock (24-48h Dispatch)
The 12A / 600V counterpart under the ST part numbering: same current class, IGT in the 5-15mA band, the same TO-220AB pinning - documented on cross lists as the direct BT151-600R replacement.
600V blocking, same class; the TYN812 covers the 800V step under the same naming.
The 800V Step Up the Ladder
Shenzhen Spot Stock (24-48h Dispatch)
The 12A die with the 800V blocking step: the part for 380-480V rails, welder crowbars and mains classes where the 600V margin was thin to begin with.
The whole point: 800V VDRM/VRRM against the 600V of the base part - same current, more transient headroom.
Buyer & Quality Checklist for Sourcing Alternatives
- The digits after the dash are the blocking voltage: -500R/-600R/-650R/-800R span 500V to 800V on the same 12A die. Match the class to the rail and its transients; the suffix letter belongs to the ordering table, not to memory.
- Gate sensitivity divides the ladder: BT151 sensitive-gate grades trigger in the 2-15mA band; BT152 and bulkier rungs can ask 15-30mA. A substituted SCR that will not latch on cold boards is usually a gate-current shortfall, not a dead device.
- SCRs are one-directional: they conduct anode-to-cathode only and turn off at the current zero crossing. Boards built around a triac (the BT136 family - one digit away in name) cannot take an SCR, and the reverse ends the same way.
- The TO-220AB tab is the anode on this family - live. Isolator bushings and creepage are part of the design; a repair that skips them puts mains potential on the heatsink.
- Crowbar and charger duty leans on surge: the ~120A ITSM class is the headline, and survival depends on the gate-cathode resistor and layout as much as the die. A repeat failure in the same socket is a drive or clamp problem first.
- In phase-control (charger) duty the trigger timing is set by the external circuit: a swapped-in SCR with a different IGT shifts the earliest firing angle - confirm the charging current profile after any substitution, not just the fact that it charges.
Frequently Asked Technical Questions
Q: Can a BT152 replace a BT151-600R?
A: Yes as an upgrade - same family, same TO-220AB body, 16-20A against 12A - with one check: BT152 grades can need more gate trigger current (15-30mA against the sensitive-gate 2-15mA band). A marginal drive circuit that worked with the small gate may not fire the bigger one.
Q: What do the digits and suffix in BT151-600R mean?
A: The digits carry the blocking voltage class - 500V, 600V, 650V or 800V of the same 12A die. Read the exact ordering-table suffix against the datasheet when reordering; the voltage number is the design-critical part.
Q: Is an SCR the same as a triac?
A: No. An SCR conducts one direction and turns off at zero current; a triac conducts both directions for full-wave AC phase control. The BT151 (SCR) and BT136 (triac) names sit one digit apart and share a drawer - and nothing else in the circuit.