How Does a Voltage Meter Work?
Whether you're troubleshooting a riding lawn mower's electrical system or diagnosing an issue with a household appliance, a voltage meter (or multimeter) is an essential tool for identifying problems and ensuring safety.
In this article, we’ll dive into how voltage meters work, their role in measuring voltage in a 12-volt DC system (like a lawn tractor), and how they can help diagnose electrical issues in everyday devices.
KEY TAKEAWAYS
- A voltage meter is an essential tool for measuring electrical potential in both DC systems (like lawn tractors) and AC systems (like household appliances). It helps troubleshoot issues such as low battery charge, faulty components, or wiring problems.
- When using a voltage meter, always set it to the correct mode (DC or AC), inspect probes for damage, and wear protective equipment such as gloves and goggles for safety. For appliances, disconnect power before disassembly to safely measure resistance and diagnose failures.
- Voltage meters are indispensable for testing wiring and electrical components in home appliances and lawn equipment. Learning to use this tool effectively can save you time and money, enabling you to safely complete DIY repairs.
What is a Voltage Meter?
A voltage meter measures the electrical potential difference (voltage) between two points in an electrical circuit.
Most voltage meters include modes for measuring electrical resistance and current so they’re commonly called multimeters.
The voltage mode on a multimeter can measure these 2 different types of electrical voltage:
- DC Voltage -- For direct current (DC) systems, such as batteries, lawn & garden equipment such as riding mowers and automotive circuits.
- AC Voltage -- For alternating current (AC) systems, like household outlets and home appliances.
How Does a Voltage Meter Work?
A voltage meter measures how much voltage passes between two points in an electrical circuit.
It does this by determining the difference between the positive input of voltage and the negative input of voltage. Here's how it works:
Probe Connection
The voltage meter has two probes: a red probe for the positive terminal and a black probe for the negative terminal (ground).
When connected to a circuit, it forms a low-resistance path for current to flow momentarily.
Voltage Measurement
The meter detects the potential difference (voltage) between the two points where the probes are connected.
This difference is displayed on the screen in volts (V).
Safety
Most meters have built-in overload protection to prevent damage if accidentally connected to a voltage higher than its capacity.
How to Use a Voltage Meter in a Riding Lawn Mower 12-Volt DC System
A 12-volt DC battery powers the electrical system powers many lawn tractors. The battery sends current to various electrical components such as the starter, lights, and ignition system.
Here's how to use a voltage meter to measure and diagnose problems in a DC system:
Wear Gloves and Safety Goggles
Wear insulated safety gloves and protective eye goggles when checking voltage in a riding mower.
Turn off the riding mower engine if you don’t need it running when checking voltage.
Avoid contact with moving parts, wiring and adjacent metallic surfaces when taking voltage readings.
Set the Meter
Turn the multimeter on and set it to measure DC voltage. Ensure the meter voltage range is properly (at least up to 20V) for a 12V system riding mower electrical system.
Test the Battery
When troubleshooting riding mower electrical problems, you’ll typically need to test the battery using a voltage meter to determine whether the battery has an adequate charge to supply current through the riding mower electrical system.
To check the battery’s charge, connect the meter red probe to the battery's positive terminal (+) and the black probe to the negative terminal (-).
A healthy 12V battery should read between 12.4V and 12.6V when fully charged.
If the voltage is below 12V, the battery needs charging or replacement.
Testing Specific Riding Mower Circuits
Most of the time, you’ll reach for a voltage meter to test circuits and components in your riding mower when it won’t start. Checking for voltage at specific points in a circuit will tell you whether a fuse is blown, a switch is bad or a component has failed.
To see specific examples of how to use a voltage meter to diagnose a common starting problem in a riding lawn mower, view this popular DIY video:
When you’re unable to diagnose and fix a riding mower starting problem on your own, schedule riding mower repair service and we’ll send a Sears Home Services technician to your home to fix the starting issue.
Using a Voltage Meter with Household Appliances
Although professional service technicians often use a voltage meter to diagnose and repair home appliances, DIY’ers should only use electrical resistance settings on the meter to check for problems and failed components in AC circuits.
You should always unplug a home appliance to disconnect electrical power before disassembling and diagnosing or repairing a failure.
Checking live voltage in an appliance is extremely dangerous for DIY’ers because making contact with electrically energized components or wiring inside the appliance can result in lethal electrical shocks.
Here’s a video that shows how to use a multimeter to safely check resistance through circuits and components in an appliance to diagnose a failure:
Here’s a popular DIY troubleshooting video that shows details of how to use a multimeter to check circuits and components in a clothes dryer that won’t heat:
If you’re unable to diagnose and repair an appliance failure on your own using resistance measurements, schedule appliance repair service and we’ll send a Sears Home Services technician to your home to fix the problem.
Safety Tips When Using a Voltage Meter
Follow these safety tips when using a voltage meter:
- Double-Check the Meter Settings: Always confirm the meter is set to the correct mode (DC or AC), measurement setting and range.
- Inspect Probes and Leads: Look for damage that could compromise safety. Replace probes if wiring or insulation is damaged.
- Wears Proper Protective Equipment: When checking DC voltage in riding mowers, wear insulated gloves and protective eye goggles. When disassembling and checking resistance in appliances, wear work gloves to protect your hands from sharp edges inside appliances.
- Avoid Short Circuits: Keep probes from touching each other and other live wires or components while checking live DC circuits in riding mowers.
- Disconnect Electrical Power from Appliances: Never check live AC voltage in appliances. Unplug the appliance power cord before disassembling and using a multimeter to check resistance in appliances to diagnose failures.
- Follow the Manual: Always consult your voltage meter's user manual for specific instructions.
Understanding how to safely use a voltage meter can save you time and money while giving you the confidence to tackle basic electrical repairs.
Whether you're testing a 12-volt system in a lawn tractor or diagnosing a failure in a household appliance, mastering this tool will empower your DIY projects.
With proper safety precautions in place, a reliable voltage meter can be your go-to device for troubleshooting and maintenance.
Schedule your riding mower repair now!
With years of expertise, our technicians can diagnose and repair your riding mower no matter the problem, so you can get back to mowing quickly.
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