Amprobe LM-120 Light Meter
The Amprobe LM-120 Light Meter measures visible light from fluorescent, metal halide, high-pressure sodium and incandescent sources. It displays results in lux or foot-candles, so users can work with their preferred unit. Its portable form also supports simple one-handed testing in commercial and industrial areas.
Use the meter to check light levels inside offices, workshops, public buildings and other indoor spaces. Clear readings help users decide whether lighting output should be raised, reduced or switched off. As a result, regular checks can support a more efficient lighting system.
Wide Measurement Coverage
With a maximum capacity of 200,000 lux or 20,000 foot-candles, the Amprobe LM-120 Light Meter covers both low and high light levels. Automatic ranging selects a suitable range, while manual control lets the user choose one directly. Therefore, the meter adapts easily to varied testing tasks.
A silicon photodiode sensor and filter detect the light that reaches the separate sensing head. The unit samples 2.5 times per second and presents the result on a large 3½-digit LCD. It also provides 0.01 foot-candle or 0.1 lux resolution where the selected range allows it.
Simple Reading Control
Data Hold freezes the displayed value, making it easier to record a result after moving away from the test point. In addition, minimum and maximum modes show the lowest and highest readings found during a test. The Amprobe LM-120 Light Meter also includes a zero function to null the display before measurement.
Automatic power-off operates after about six minutes to help protect the supplied 9 V battery. A low-battery symbol warns when the battery voltage drops below the working level. Two meter set types are available in the series, with the LM-100 offering manual ranging and the LM-120 providing automatic and manual ranging.
Key Features
- Front-panel switching between lux and foot-candle units
- Automatic ranging for quick changes between light levels
- Manual range control for direct user selection
- Data Hold freezes a reading on the digital display
- Minimum mode records the lowest measured value
- Maximum mode records the highest measured value
- Zero control helps null the display before a test
- Separate sensor head supports practical position checks
- Protective sensor cap helps guard the sensing surface
- Low-battery indication warns when power is reduced
- Automatic polarity and negative polarity indication
- Overrange warning displays OL or -OL on the screen
- Portable design supports simple one-handed operation
- Automatic shut-off helps extend battery working time
- Supplied carrying case helps protect the meter in transit
Technical Specifications
| Product name | Amprobe LM-120 Light Meter |
| Measurement type | Visible light level measurement |
| Supported light sources | Fluorescent, metal halide, high-pressure sodium and incandescent |
| Measurement units | Lux and foot-candles |
| Ranging | Automatic and manual |
| Lux ranges | 20, 200, 2,000, 20,000 and 200,000 lux |
| Foot-candle ranges | 20, 200, 2,000 and 20,000 foot-candles |
| Resolution | Up to 0.1 lux or 0.01 foot-candle, depending on the selected range |
| Sensor | Silicon photodiode and filter |
| Calibration point | 2854 K cosine angular corrected per JIS C 1609:1993 and CNS 5119 general A class |
| Display | 3½-digit liquid crystal display with a maximum reading of 1999 |
| Sampling rate | 2.5 readings per second |
| Polarity | Automatic with positive implied and negative polarity indication |
| Overrange indication | OL or -OL displayed |
| Data functions | Data Hold, minimum reading and maximum reading |
| Zero function | Yes |
| Accuracy | ±3% when calibrated to a standard incandescent lamp at 2854 K and 6% for other visible light sources |
| Low-battery indication | Battery symbol appears when voltage falls below the operating level |
| Operating temperature | 14 °F to 104 °F, equivalent to -10 °C to 40 °C |
| Operating humidity | 0 to 80% RH |
| Storage temperature | 14 °F to 122 °F, equivalent to -10 °C to 50 °C |
| Storage humidity | 0 to 70% RH |
| Maximum operating altitude | 2,000 metres for indoor operation |
| Power supply | 9 V NEDA 1604, IEC 6F22 or JIS 006P battery |
| Battery life | Approximately 200 hours |
| Automatic power-off | Approximately six minutes |
| Base dimensions | 5.1 × 2.5 × 1.5 inches, equivalent to 130 × 63 × 38 mm |
| Sensor dimensions | 3.2 × 2.2 × 1.1 inches, equivalent to 80 × 55 × 29 mm |
| Weight | 0.48 lb or 220 g, including the battery |
| Approval | CE, EMC EN61326-1 |
Comparison Table
| Feature | LM-100 | LM-120 |
|---|---|---|
| Ranging method | Manual | Automatic and manual |
| Lux ranges | 200, 2,000, 20,000 and 200,000 | 20, 200, 2,000, 20,000 and 200,000 |
| Foot-candle ranges | 20, 200, 2,000 and 20,000 | 20, 200, 2,000 and 20,000 |
| Silicon photodiode sensor and filter | ✓ | ✓ |
| Data Hold | ✓ | ✓ |
| Maximum reading mode | ✓ | ✓ |
| Minimum reading mode | — | ✓ |
| Zero function | — | ✓ |
| Automatic power-off | — | ✓ |
Document Downloads
What’s Included
- Amprobe LM-120 Light Meter
- 9 V battery
- Carrying case
- Protective sensor cap