
The LAH125-P is a closed-loop compensated Hall-effect current sensor from LEM, the global leader in electrical measurement. Designed for high-precision electronic measurement of DC, AC, and pulsed currents, this sensor expands the LAH series with a 125A rated current capability, sitting alongside existing 25A, 50A, and 100A models. With galvanic isolation between the primary and secondary circuits, it delivers high accuracy, excellent stability, and strong anti-interference performance – making it an ideal choice for industrial automation, variable frequency drives, power supply management, and more.
Total error at rated current is as low as ±0.41%, with linearity error below 0.15%. The closed-loop compensation technology eliminates Hall element temperature drift and non-linearity, ensuring consistent measurement performance.
Response time is only 1μs, and delay time (10% step) is less than 500ns – capable of tracking current slew rates exceeding 100A/μs. Whether for overcurrent protection or closed-loop control, the sensor reacts almost instantaneously.
Frequency bandwidth DC to 100kHz (-3dB), covering everything from DC bus monitoring to high-frequency switching currents.
Operating temperature range from -40°C to +85°C with low drift. Verified in real tests: offset current temperature drift is only ±0.22 to ±0.65mA over -25°C to +70°C.
AC insulation test voltage: 5kV rms (50Hz, 1 minute); impulse withstand voltage: 12kV (1.2/50μs). Compliant with EN 50178 and IEC 61010-1 basic and reinforced insulation requirements. Galvanic isolation ensures complete separation between primary power circuits and secondary electronics, protecting sensitive devices.
Closed-loop Hall technology effectively suppresses external electromagnetic interference. Excellent overload capability ensures reliable operation even under sudden load surges.
PCB through-hole mounting with a footprint under 6cm², height of only 27mm, and weight of 30g. The insulated plastic housing meets UL 94-V0 flammability rating for safety.
|
Parameter |
Value |
|
Rated measuring current (IPN) |
125 A rms |
|
Measuring range (IPM) |
0 … ±200 A |
|
Turns ratio |
1 : 1000 |
|
Secondary rated signal (ISN) |
125 mA |
|
Supply voltage |
±12V … ±15V (±5%) |
|
Supply current (max) |
144mA |
|
Accuracy @ 25°C |
±0.41% |
|
Linearity error |
< 0.15% |
|
Bandwidth (-3dB) |
DC … 100 kHz |
|
Response time (90% step) |
< 1 μs |
|
Delay time (10% step) |
< 500 ns |
|
Operating temperature |
-40°C … +85°C |
|
Storage temperature |
-40°C … +90°C |
|
AC insulation test voltage |
5 kV rms / 50 Hz / 1 min |
|
Mass |
30 g |
|
Mounting type |
Through-hole (PCB) |
The LAH125-P is already widely used in the following applications, proven by thousands of customers worldwide:
Variable frequency & servo drives – Current closed-loop control in AC drives and servo motor drives
Power supplies – Current sensing and protection in SMPS, UPS
DC motor drives – DC motor current monitoring in static converters
Battery-powered equipment – Real-time battery charge/discharge current monitoring
Welding power supplies – Precise current control in welding processes
Renewable energy – Power monitoring in PV inverters, wind power converters
|
Comparison |
Traditional Solutions |
LAH125-P |
|
Accuracy |
Lower |
±0.41% – precise & reliable |
|
Response speed |
millisecond level |
microsecond level – <1μs |
|
Isolation voltage |
Limited |
5kV high isolation |
|
Temperature adaptability |
Restricted |
-40°C ~ +85°C |
|
Interference immunity |
Average |
Closed-loop Hall, high immunity |
|
Ease of integration |
Complex external circuitry |
PCB through-hole, plug-and-play |
| Our advantage is that we not only low prices, but we more suited to you. Our Keywords is New and original parts Fast Delivery Instock & available Short Leadtime 30-Days returns ISO9001 Certification 1 Year Warranty |
|
Q: I want to work with MacroQuest because of high quality. But I found your price too high and out of line with the prevailing market level, how should I do?
A: MacroQuest has been devoted to offer a best price to our customers,if you want to buy it at a cheapper price. Please contact us directly to see if we can negotiate a cheaper price rate. Or, send us an email with your T/P.
Simon Hsu
simon@mymacroquest.com
Alice Wang
alice@mymacroquest.com
Q: Can MacroQuest offer NET terms?
A: Yes we can. Please contact with your sales manager for more information.
Q: How to Request a Quote?
-A:You have three ways to request a quote:
1.Choose an item using a search box or browsing through product categories.Click on "Request Quote" button on the Product page.
2.Click here for feedback on our web.
3.If you have a BOM list or want to email us directly, please contact:
Simon Hsu
simon@mymacroquest.com
Alice Wang
alice@mymacroquest.com
Q:Are all the parts new and original?
-A:Yes, all parts are new and original checked by our quality control department.
Q:How long is your warranty?
-A:We offer a 1 year warranty for form fit and function for MacroQuest stock.
Q: Can I use Credit Card/Debit Card payment for my orders on your website?
-A:Yes, you can. you can pay on our company via Credit Card/Debit Card(Mastercard, Discover, Visa, American EXpress, Diners).
Please select the first payment method-Paypal, then you will see Credit Card/Debit Card payment button in the lower right corner.
My Account
If you visit our website for the first time or do not have your login and password yet, please complete the new Customer Registration Form and register in our Customers’ database.
If you have an account, enter your login and password and confirm these with the “Log in” button.
If necessary, complete the contact person identification form.
Log In / Registration
Update Profile Information
Change Password
Update Addresses
Update Payment Cards
Update Order Preferences
Update Product Notifications
Product Information
Choose an item using a search box or browsing through product categories. While searching, you can use your own previously entered product symbols/references.
Searching for Products
Pricing & Availability
Packaging Options
RoHS / Legislation
Technical Support
Placing Orders
How to place an order if you have an account at MacroQuest?
Checkout
Invoicing & Payment
Delivery Information
Favourite
Parts List (BOM) Upload
Trade Account
Quotes
Quick Buy
Saved Shopping Baskets
Scheduled Orders
Vouchers
Viewing and Changing Orders
The on-line orders system within the MacroQuest’s service works at real time, thanks to which it is immediately (at the moment of placing the order) possible to make a reservation for the selected product in the warehouse what it will be automatically noted in the on-line service.
If you order a product, it will be reserved for you.
You can make changes in quantity in the cart, by adding and removing items from the not closed order, before you direct them to realization with the “finish the order” button.
Order Status & Tracking
Request an Invoice
Cancel an Order
Returning a Product
RMA# is required for all returns. They are issued for returns that are within 30 days of the initial purchase.
Return Policy
How to Return a Product


