HOW-TO GUIDE
How to Use an Analog Multimeter
An analog multimeter reads with a moving needle against a printed scale instead of a digital display, and that changes more about how you use it than it might seem. Here's what's actually different from a digital meter, and how to avoid the mistakes that are specific to analog.
Analog meters read current/voltage scales left-to-right, but the ohms scale runs backward — zero on the right, infinity on the left.
Why anyone still uses an analog meter
Digital meters are more accurate and easier to read for most tasks, which is why they've mostly replaced analog ones. Analog still has a niche: a needle shows a trend — rising, falling, fluctuating — more intuitively than a digital display that refreshes a few times a second, which some technicians still prefer for watching a value change in real time, like tuning a circuit or checking a battery under a changing load.
1Reading the scales correctly
An analog meter face usually has several curved scales printed one above another — one for DC voltage/current, one for AC, and one for resistance — and you have to read the correct one for the function and range you've selected on the dial. The resistance (Ω) scale is the one that catches people out: unlike the others, it reads backward, with 0Ω on the right and infinite resistance on the left, compressed so the low end of the scale is much easier to read precisely than the high end.
2Avoiding parallax error with the mirror strip
Many analog meter faces include a thin mirror strip running alongside the scale. Look at the needle from an angle and you'll see its reflection offset from the needle itself — that offset is parallax error, and it means you're not reading the true value. Move your head until the needle fully covers its own reflection, then read the scale; that's the only viewing angle that gives an accurate reading on an analog dial.
3Zeroing the ohms scale before every resistance measurement
Unlike a digital meter, an analog meter needs to be re-zeroed on the resistance range each time you use it, because the reading depends on the internal battery's current voltage, which drifts as the battery ages.
- Select the resistance range you plan to use.
- Touch the two probes directly together.
- Turn the dedicated "zero ohms" adjustment knob until the needle rests exactly on 0Ω (the right-hand end of the scale).
- Separate the probes and take your actual measurement.
If the needle won't reach 0Ω even with the adjustment knob turned fully, the internal battery is too weak and needs replacing before the reading can be trusted.
Resistance-range polarity is usually reversed
4Measuring voltage and current
The basic probe placement is the same as a digital meter — parallel across two points for voltage, in series for current — but two things are different in practice. First, there's no auto-ranging: you have to select the correct range yourself before measuring, and picking too low a range on an unknown voltage can pin the needle hard against the stop, which can damage the movement. Second, analog meters generally have lower input impedance than a modern digital meter, meaning the meter itself draws more current from the circuit it's measuring — on sensitive, high-impedance circuits, that can noticeably skew the reading simply by being connected.
How much does meter loading change a reading?
Analog meters state their sensitivity in ohms per volt; 20,000 Ω/V is a common figure on general-purpose meters, so check the label on the face of yours. Multiply it by the full-scale value of the range you've selected to get the meter's input resistance: 20,000 × 10 V = 200 kΩ on the 10 V range, and 20,000 × 50 V = 1 MΩ on the 50 V range. Many digital meters present around 10 MΩ on every DC voltage range. The worked example below shows what that difference does to a real measurement.
Unloaded, the midpoint sits at exactly 5 V. Seen from the meter, the circuit looks like 5 V behind 50 kΩ (the two 100 kΩ resistors in parallel). The reading is therefore 5 V × Rin ÷ (Rin + 50 kΩ). On the 10 V range, 5 × 200 ÷ 250 = 4.0 V, a 20% error. Switch the same analog meter up to the 50 V range and the reading becomes 5 × 1,000 ÷ 1,050 ≈ 4.76 V, closer to the truth even though the needle now moves only a tenth of the scale. A 10 MΩ digital meter reads about 4.98 V.
The lesson is practical: on low-impedance circuits such as a battery, a car electrical system or a power supply output, an analog meter's loading is negligible and you can trust it. On high-resistance points, like a sensor signal, a bias network or a divider made of large resistors, either use a digital meter or move to a higher range and accept the coarser scale. If two ranges give noticeably different answers, loading is the reason, and the higher range is the more honest one.
Common analog-specific mistakes
- Reading the wrong curved scale for the function and range actually selected on the dial.
- Skipping the zero-ohms adjustment before a resistance measurement, which makes every reading on that range wrong by the same offset.
- Starting on too low a voltage or current range for an unfamiliar circuit, risking a pinned needle.
- Assuming red is always positive, even on the resistance range where it typically isn't.
Frequently asked questions
How do you use an analog voltmeter?
Select the voltage range above what you expect to measure (there's no auto-ranging), connect the probes in parallel across the two points — red to the more positive point, black to the other — and read the needle against the correct curved scale for that range. View the needle straight-on against its mirror strip to avoid parallax error, which otherwise shifts the apparent reading.
Why does the ohms scale on an analog multimeter read backward?
It's a consequence of how the meter's moving-coil mechanism responds to current: more current through the coil (lower resistance) swings the needle further, so 0 Ω sits at the high-current end (right) and infinite resistance sits at the low-current end (left) — the opposite of the voltage and current scales. The scale is also compressed at the high-resistance end, which is why low readings are easier to read precisely than high ones.
What is parallax error and how do you avoid it?
Parallax error is the apparent shift in a needle's position when you view it from an angle instead of straight on, caused by the gap between the needle and the scale printed behind it. Many analog meters include a mirror strip alongside the scale specifically to catch this: move your head until the needle fully covers its own reflection, then read the scale from that angle.
Can an analog multimeter measure both AC and DC?
Yes — the dial has separate AC and DC ranges, and probe placement is the same as a digital meter: parallel across two points for voltage, in series for current. What's different is there's no auto-ranging, so starting on too low a range on an unfamiliar circuit can pin the needle hard against its stop and damage the movement.
Is an analog multimeter ever better than a digital one?
For most tasks, no — digital meters are more accurate and easier to read. The one niche where analog still has an edge is watching a value change in real time, such as tuning a circuit or checking a battery under a changing load: a moving needle shows a rising, falling or fluctuating trend more intuitively than a digital display that only refreshes a few times a second.
