Free shipping to the lower 48 US states. International orders ship by DHL. Education pricing for schools.
Decade box on an ego trip
Precision programmable resistors. Same idea, two ranges. Real relays, real resistors, and both run sensor tables. Which one fits?
For high resistance.
$987
In the box: one set of test leads.
Ships from Scottsdale, AZ. Free shipping to the lower 48 US states. International orders ship by DHL: request a quote.
Schools: 30% off with verification. Request education pricing.
Send it to us. We send it back.
We recommend calibrating every 2 years. Send your box to us and get it back with a certificate and a free firmware upgrade, or do it yourself with the Companion app and your own meter.
v7.xRunning firmware before 7.x? Those boxes can't use the Companion app and can't be upgraded in the field. Send yours to us and we'll bring it up to the newest firmware.
Neither model is better. They cover different ranges and step sizes.
Neither model goes below 1 Ω.
Match
Check what you need.
Pick what you need to simulate and this updates.
Both models side by side, from the operation manual, rev C.
| Parameter | ohmSTAR | ohmSTAR+ |
|---|---|---|
| Price | $987 | $1,024 |
| Range | 1 Ω to 25 MΩ | 1 Ω to 5 MΩ |
| Resolution | 0.1 Ω | 0.01 Ω |
| Accuracy at 25 ±2 °C | ±0.5 Ω below 1 kΩ±0.1 % from 1 kΩ to 1 MΩ±0.5 % above 1 MΩ | ±0.2 Ω below 1 kΩ±0.05 % from 1 kΩ to 1 MΩ±0.5 % above 1 MΩ |
| Power rating | 1 W max | 1 W max |
| Calibration | 26-point field calibration | 30-point field calibration |
| Switching | Mechanical relays, full relay isolation | Same |
| Protection | Current limiter (I set). Open key disconnects mechanically. | Same |
| Control | Keypad, encoder wheel, USB | Same |
| Computer interface | USB serial, 9600 baud, 8N1 | Same |
| Memory | 4 quick keys (A–D), 10 memories | Same |
| Display | Graphic LCD; unit and resistance together | Same |
| Sensor types | Pt RTD, NTC thermistor, strain gauge, conductivity, potentiometric, custom table | Same |
| Lookup tables | Up to 256 points each, from a .txt file | Same |
| Power | Battery. Over 1 year battery life. Auto-off after 4 min. | Same |
| Size | 6.7 × 3.5 × 1.6 in (17 × 8.7 × 4.1 cm) | Same |
| Weight | 13.8 oz (392 g) | Same |
| Included | Test leads | Test leads |
| Warranty | Lifetime warranty, original US purchaser | Same |
| You're simulating | Pick | Why |
|---|---|---|
| Pt100 or Pt1000 RTD | Either | A 0.1 Ω step is about 0.26 °C on a Pt100; 0.01 Ω is about 0.026 °C. |
| 350 Ω strain gauge | Either | At GF 2.0, 0.1 Ω is about 143 µε per step; 0.01 Ω is about 14 µε. |
| 10k NTC thermistor | Either | About 402 kΩ at −40 °C (β 3950). Both models cover it. |
| 100k NTC, cold end | ohmSTAR | Passes 5 MΩ below about −43 °C. |
| Megohm loads, insulation tests | ohmSTAR | Goes to 25 MΩ. |
| Fine steps: 0.01 Ω resolution | ohmSTAR+ | Steps in 0.01 Ω. ohmSTAR steps in 0.1 Ω. |
| Above 5 MΩ and 0.01 Ω steps | One of each | They share leads, tables and software. |
°C and µε per step are calculated from standard sensor slopes. They aren't an accuracy spec.
Not sure? Email mike@maxmetrix.com with your sensor and range and we'll tell you.
You can get resistance lots of ways. Here's the honest comparison.
| ohmSTAR | Manual decade box | Fixed resistors | Potentiometer | Process calibrator | |
|---|---|---|---|---|---|
| Set a value | Keypad, encoder, USB | Thumbwheels / rotary | Find it, solder it | Turn and measure | Menus |
| Sensor tables (°C on screen) | Yes, custom loadable | No | No | No | [varies by model] |
| Computer control | USB | No | No | No | Some models |
| Value holds after setting | Yes, latching relays | Yes | Yes | It drifts | Yes |
| Real resistance | Yes | Yes | Yes | Yes | Often electronic |
| Best at | Repeatable, scriptable, sensor-aware | Already on your shelf | One value, forever | Quick and rough | Multi-signal field work |
Comparison is by category, not by product. Your calibrator may differ.
Yes. The USB link is two-way, so a script can set values and read them back. See the command reference. The ohmSTAR Companion desktop app is out now for Windows, Mac and Linux. Download it from Resources.
Both models are rated 1 W max. Before you connect, press I set and enter your application voltage; the current limiter then blocks low values that would draw too much current.
Yes. Read it in the manual flipbook on Support.
