BGH-1120A
ActiveVariable Speed Trigger Switch 20.1A 42V DC
Defond variable speed trigger switch — found in most power tools globally.
Common Applications
Defond is the worlds largest trigger switch manufacturer — if your power tool was made in China (most are), the trigger is almost certainly Defond. 20A continuous rating handles the heaviest cordless tools. Variable speed with electronic speed control integration. Found in Black+Decker, DeWalt (TTI), Ryobi, and hundreds of other brands.
Research Notes
1. Overview
Defond (Hong Kong) is an OEM/ODM switch maker supplying trigger switches and battery-management electronics to the power-tool industry — 50M+ units/year, parts embedded (unbranded) in tools from brands like Milwaukee and Bosch. Defond groups trigger switches into named families: BGV (overhang trigger), DGQ (Euro-style AC trigger), CGJ (variable-speed with battery-protection), and BGH, a DC series for cordless tools, alongside sibling DC families BGC/BGL/BGN. BGH-1120A is the specific orderable member: a variable-speed (VSC) trigger switch rated 42 V DC / 20.1 A, for ~36V-class cordless drills/drivers (42V max = fully-charged 10-cell Li-ion pack).
2. User Sentiment
No meaningful consumer sentiment exists — this is a bare internal sub-component, not something end users evaluate on its own. Listings (eBay, Amazon, AliExpress, Fruugo, PicClick) are generic parts-resale posts with little review activity. Repair forums discuss "Defond trigger switches" as a failure-prone category in cordless drills generally, but none discussed BGH-1120A by exact model. Sentiment: essentially none reported, typical of a low-visibility OEM part.
3. Real-World Applications
BGH-1120A is a cordless drill/driver-class trigger switch. No source names a specific host tool model/brand — sellers market it generically as a "power drill switch" replacement, implying broad compatibility across similarly-rated ~36V cordless tools rather than one named OEM host.
A widely-repeated Milwaukee cross-ref (23-66-0445, "Variable Defond Switch 125V," fitting corded Milwaukee 0240-20) turned out not to be this part: the Defond model behind 23-66-0445 is DGQ-1110B (10A/125VAC, AC corded family) — different family/voltage/current class than BGH-1120A. See Section 5.
4. Technical Specifications
- Type: Electronic variable-speed (VSC) trigger switch, DC (BGH family)
- Voltage: 42 V DC
- Current: 20.1 A ("20.1RA"/"20.1A")
- Mechanical/electrical life: 5E4 rating (~50,000 cycles) — matches Defond's published 5E4 rating on sibling DC families (BGV, CGJ)
- Certifications: not directly confirmed for -1120A; sibling families (CGJ, DGQ, BGV) publish cULus/ENEC/CQC, so similar certification is plausible but unconfirmed here
5. Ordering & Compatibility
The correct, complete orderable part is BGH-1120A — every source (eBay, Amazon, Walmart, AliExpress, Alibaba, Fruugo, PicClick, 1SourceComponents) uses the full "-A" suffix; none show bare "BGH-1120" sold or spec'd standalone. Cross-referenced Defond internal codes tied to this part: 760526010, 760526013, 760526022 — most likely lot/date-code or customer-packaging variants of one switch, not separate models.
Aftermarket availability is decent: Amazon, Walmart, eBay, AliExpress, Fruugo stock replacements around $18–$40 USD. 1SourceComponents (US distributor) also lists it for quote.
Correction to a suspected cross-ref: Milwaukee 23-66-0445 traces to Defond DGQ-1110B (10A/125VAC), not BGH-1120A — treat that pairing as unrelated pending stronger evidence.
6. Known Issues
No documented failure writeups or teardowns specific to BGH-1120A were found. General risk for electronic VSC trigger switches (onboard FET) is thermal degradation of the FET or potentiometer contacts under sustained heavy load — why these ship as drop-in service parts rather than field-repaired. No recalls or complaint patterns found for this part number.
15 sources
- Variable Speed Trigger Switch with Battery Protection Electronics (CGJ) - Defond — defondetech.com
- Trigger Switch with Variable Speed Control - Euro Style (DGQ) - Defond — defondetech.com
- Overhang Trigger Switch (BGV) - Defond — defondetech.com
- DC Switches - BGH - Defond — defondetech.com
- Power Tools | Intelligent Power Tools Solutions - Defond — defondetech.com
- Defond Switch BGH-1120A 20.1RA 42Vd.c. 5E4 1Pcs — ebay.com
- 1PCS New For Defond Speed Switch BGH-1120A 20.1RA 42VDC — amazon.com
- For Defond Bgh-1120a 42vdc 20.1ra 5e4 760526013 Trigger Switch Electric Drill — aliexpress.com
- BGH-1120A 42VDC 20.1RA Power Drill Switch 760526010 for Defond — fruugo.us
- 1pc Defond BGH-1120A 42VDC 20.1RA 760526022 Trigger Switch — picclick.com
- Variable Defond Switch 125V 23-66-0445 - OEM Milwaukee — ereplacementparts.com
- Milwaukee VARIABLE DEFOND SWITCH 125V 23-66-0445 — mmtoolparts.com
- BGH-1120A Part Info & Rapid Quote Request — 1sourcecomponents.com
- Defond BGH-1115Z 15A 62V Trigger switch Assembly control kit 90632461 — ebay.com
- DEFOND BGC-1120C Trigger Switch 20.1RA 36Vd.c. 1E4 U.T. — ebay.com
Specifications
|
Contact Configuration
The electrical switching arrangement.
|
Variable speed (electronic)
|
|
Current rating
|
20.1A
|
|
Mechanical Life
How many press cycles before mechanical failure. Higher is better — 10M cycles at 100 presses/day = 274 years.
|
50,000 cycles (5E4)
|
|
Voltage
|
42V DC
|
Installation Quick Reference
Panel cutout: 22mm. Insert from the front of the panel, secure with mounting nut from behind (tighten to 2-3 Nm).
Contact block: Snap or screw the contact block onto the rear of the button body. Ensure the contact block orientation matches the wiring diagram — NO terminals are usually marked.
Wiring: Use 0.5-2.5mm² stranded wire with ferrules. Tighten screw terminals to 0.8 Nm. Test the button function before energizing the circuit.
Dimensions
Wiring Diagram
Troubleshooting
Button doesn't respond when pressed
Check the contact block first — it's the most common failure point. Test continuity across the NO or NC terminals with a multimeter. If no click is felt, the return spring in the head may be broken.
Works intermittently
Contact block contacts are pitted or burned. Replace the contact block — don't try to file the contacts. Check if the rated cycle count has been exceeded.
Button feels mushy or doesn't click
The spring return mechanism in the button head is worn. Replace the head. The contact block can usually be reused if it tests OK.
Where to Buy
Price range
$32.32 — $42.09
across 2 sellers in US dollars
Quick Specs
- Contact Configuration
- Variable speed (electronic)
- Current rating
- 20.1A
- Mechanical Life
- 50,000 cycles (5E4)
- Voltage
- 42V DC
What People Are Saying
“Defond is the worlds largest trigger switch manufacturer — if your power tool was made in China (most are), the trigger is almost certainly Defond. 20A continuous rating handles the heaviest cordless ”