Watt’s Up: News and Shocks from Electrotest⚡

Now for something from the Service Department... 

Jon Forster 

Accuracy and resolution explained briefly:

Accuracy and resolution in a multimeter are two distinct but crucial aspects that determine measurement quality. Accuracy refers to how close the measured value is to the actual, true value of the quantity. It is typically expressed as a percentage of the reading, sometimes with an added fixed digit value (for example, ±(1% + 2 digits)). High accuracy means the measurement you read is very close to the real value being measured.

Resolution, conversely, is the smallest change or increment the multimeter can detect or display. It is usually defined by the number of digits or “counts” the meter can show. For example, a 4½-digit meter offers higher resolution than a 3½-digit meter, because it can display finer distinctions in the measured values—even if its accuracy hasn’t improved.

A key point is that higher resolution allows the user to see smaller changes in the signal, but does not guarantee that the measurement is actually correct. A multimeter with high resolution could still be inaccurate if its readings aren’t close to the true value. Ultimately, accuracy describes correctness, while resolution describes fineness and detail in what you see. The best digital multimeters offer both high accuracy and high resolution for detailed and trustworthy measurements.

By way of practical application, it’s important to note that the resolution of the multimeter when measuring low resistances (especially <0.5Ω) exceeds its accuracy due to the nature of 2-wire measurement of low resistance values, artifacts of contact resistance greatly affect results.

For accurate low resistance measurements, a 4-wire Kelvin measurement is needed, however that’s a chapter for another time.

And here’s a graphical representation to finish:

Dialling In Some Laughs

Tip of the Month: Keep Your UPS Happy – Smart Tricks for Reliable Power 💡

UPS systems keep critical gear running, but many failures come from missed maintenance or setup errors - not hardware. This month, we’re sharing quick troubleshooting and efficiency tips for technicians and users of INVT, ABLEREX, and Kehua Tech UPS systems..

1. Start with the Basics
Always do a quick visual check: loose connections, blocked vents, corroded or bulging batteries, and ambient temperature above 25°C. A clean, cool, dry environment with proper vent clearance dramatically extends UPS life.

2. Check Alarms & Logs First
Before resetting any alarms, record fault codes and timestamps. Reviewing patterns helps identify whether issues are environmental, load-related, or internal.

3. Battery Health Matters
Over 70% of UPS failures are battery-related. Check float voltage, internal resistance, and replace batteries older than 4–5 years. Rotate hot-swappable modules to prevent uneven wear.

4. UPS ≠ Total Protection
A UPS is one layer of protection. Complement it with surge protection, proper grounding, and regular load testing to safeguard sensitive equipment.

5. Efficiency Hack
Enable ECO or Smart modes when suitable to reduce energy use by 2–5% annually without compromising reliability.

When to Call for Service

• Persistent alarms or faults

• No power or response

• Suspected internal component failure

• Dangerous voltages inside the unit

At Electrotest, our certified engineers provide UPS service, preventive maintenance, and troubleshooting for all major brands, including INVT, ABB, ABLEREX, and Kehua Tech, anywhere in New Zealand. From routine checks to urgent repairs, we keep your systems reliable and ready.                                                                                     

Have any UPS Question? Get in Touch With Our UPS Expert Today 

Don't Miss Out On These BIG Sales! (All prices excl GST)

Key Information

Thank you for your support throughout the year! Please note our office will be closed from Friday, 19th December 2025, reopening on Monday, 5th January 2026.

Wishing you a Merry Christmas and a Happy New Year!