A multimeter is – in simple terms – an ammeter. Not only as a hobby electrician, you benefit from the digital multimeters presented here in your work with electricity. High-quality multi-function current testers make it easier for you to work on the construction site, in scientific research and in electrical companies. In addition to professional current controllers, we present variants that are ideal for use in the hobby sector. All digital multimeters featured on STERN.com have high-quality overload protection so you can use them safely at any time.
You also do not have to worry about setting errors in the measuring range: In the event of overloading, the device sends you visual and audible warning signals. In this case, cancel your current measurement, set the parameters correctly and then carry out the measurement again. Inform yourself in the guide about the functionality and optimal use of modern digital multimeters. The handy measuring devices are available in different sizes and designs. If required, many models can be easily transported in the jacket pocket or have holding clips for the belt.
Top 10 Multimeters
- Multimeter measures up to 1000V AC/DC voltage, 10A AC/DC current and 40MOhms resistance plus temperature, capacitance, frequency, duty-cycle, test...
- Digital Mulimeter has CAT IV 600V / CAT III 1000V safety rating
- Built to endure a 6.6-foot (2 m) drop and withstand daily wear and tear on the job site
- Wide Range of Applications: It can measure AC voltage and DC voltage, resistance, and current, It can also test circuit continuity, battery quality,...
- High Quality Display with Backlight Function: It features a high quality 3 and 1/2 digits display with maximum display value of 1999. It also features...
- BATT function to test battery quality: it displays the current (in mA) that the battery can provide when connected to a resistive load of 40 Ohms...
- 【100% Safety Assurance】Built-in Double Fuse. Overload Protection on all ranges.
- 【Auto-ranging Tester】Accurately measure AC/DC voltage, AC/DC current, resistance, frequency, continuity, diode, etc.
- 【Backlight Display】 Designed with 3 1/2 digit LCD display and 'Backlight', showing the reading clearly in low light areas.
- Multimeter measures up to 600V AC/DC voltage, 10A AC/DC current and 40 MOhms resistance
- Electrical tester measures temperature, capacitance, frequency, duty-cycle, and test diodes and continuity
- CAT III 600V safety rating
- Versatile Digital Multimeter - Accurately measures AC/DC Current, AC/DC Voltage, Capacitance, Frequency, Duty Cycle, Resistance, Diode, Continuity and...
- Thoughful Design - Support Data Hold, Large LCD Backlit Screen, Auto Shut-off and Hanging Magnet, and Kickstand make the process of measurements...
- Suitable For Many Occasions - This Multimeter is a golden partner to help to troubleshoot a variety of automotive and household electrical problems...
- VERSATILE DIGITAL MULTIMETER - Accurately measures AC/DC Voltage, DC Current, Resistance, and Diode. This Multimeter is a really useful tool for...
- TROUBLESHOOTING WITH Accuracy - This Multimeter has a sampling speed of 2 times per second; Built-in a backlight LCD display with 3 ½ digits (1999...
- ENSURES SAFETY - Double ceramic fuse is anti-burn and protects from overloading.The silicone cover is able to protect the multimeter from failing...
- True-RMS clamp meter: This multimeter can accurately measure AC/DC Current, AC/DC Voltage, Frequency or Duty Cycle, Resistance, Capacitance and also...
- LowZ & LPF: Low input impedance helps prevent false readings due to ghost voltage. Low Pass Filter (LPF) for accurate measurement of variable...
- NCV Detection Function: Non-contact voltage detection effectively check electrical status through measuring EM field intensity without touching any...
- The 117 multimeter measures AC and DC voltage as well as AC and DC amps. The 323 clamp meter measures AC and DC voltage as well as AC amps
- The 117 multimeter features true RMS for accurate measurements on non-linear loads
- The 117 multimeter features low input impedance which helps prevent false readings due to ghost voltage
- Dual display. True RMS. Basic DC accuracy: 01 percent
- Dcv/dci, acv/aci, 2/4 wire R, C, CONT, diode, freq, period, Temp
- Built-in cold junction compensation for TC temperature measurements
- Customer Service: KAIWEETS provides a lifetime after sale service and technical support. This digital multimeter is included with 2 AAA batteries...
- Multi-Function: This multimeter can test AC/DC Voltage, DC current (Can not for AC current), Resistance, Continuity, Diode Measurement.
- Sensitive Test: Please make sure the rotary switch is located at the right test range. Data hold function, backlight function helps you test clearly...
Structure, components and mode of operation of digital multimeters
A DMM (Digital Multimeter) is an electronic meter for electricity. It displays the measured values clearly as a numeric value in the display. You can carry out a variety of current tests with it. Even cheap measuring devices for hobby use measure the default values of electrical voltage, electrical current and ohmic resistance. This is usually also possible in DC circuits as in AC (AC or DC). High-quality professional current testers have additional options and continue to measure:
- The electrical capacity
- The inductance of components
- The temperature
- The frequency of the flowing current
In continuity measurements, an acoustic signal is usually available. In a digital multimeter, the signals are recognized by an analogue-digital converter and displayed as a numeric value in the display. This is usually illuminated, the numbers are displayed very large. This enables you to quickly record the measured values, even without bringing the multimeter close to your eyes. They can test current in the measuring ranges from 200 millivolts to 1,000 volts, as well as from 20 μA to 20 A. By manufacturer, some digital current controllers may deviate from these values and limit the measurement space. The built-in high internal resistance of a digital multimeter is generally between 1 and 20 MΩ, most ammeters have a resistance of 10 MΩ. High-quality digital multimeters check circuits even more precisely and have an error limit of less than 0.2 per cent. Such devices are usually relatively expensive.
Current measurement with a modern digital multimeter
To test the current intensity, the device measures the voltage via a switchable shunt resistor. It is a term from electrical engineering, which is also referred to as a current measuring resistor or shunt resistance. This electrical resistance is low impedance and is used to measure electric current. When current flows through the shunt, it causes a voltage drop that is proportional to its magnitude. This voltage drop is measured by the digital multimeter, converted to a readable value and displayed on the display. Many devices have a data hold function that lets you easily store measurement results.
Resistances measure with a digital multimeter
Even with a resistance measurement, the device detects the voltage that prevails in the circuit under test. The measured values in the display are calculated by the device on the basis of a constant current source. It can be assumed that within an electrical circuit, a constant electric current flows, which is constant regardless of the electrical voltage at the connection points at all points of the circuit.
- Mechanically simple construction
- Easy to manufacture electronic components – thus low purchase price
- Cheaper than high-quality analogue devices with the same scope of performance
- Units of measure appear on the display
- The operation of digital multimeters is very simple
- Most multimeters have overload protection and protection against reverse polarity
- Even when falling or bumping the sensitive mechanism in the meter will not be damaged, many digital current testers also have a case or a sturdy protective cover for even more security.
- Acoustic continuity tester
- Useful additional functions possible, for example, measurements of the sound or the humidity
- Digital multimeters are always dependent on an external power supply (mostly batteries, rarely batteries)
- Cheap models do not test diodes or measure temperature
Where can you use digital multimeters?
Use your compact current tester wherever you want to check an electrical circuit. Many gauges also work contactless so you can check the wiring in the wall. Common applications for True-RMS multimeters are:
- Electrical engineering as a hobby
- Electrician at work
- Standard tool in electrical companies
- School and University (Research)
What is DC? What is AC?
- Direct current
DC current flows constantly in the same direction, also the strength does not change. Frequently colloquially DC and DC are confused with each other, with DC sources produce a DC in the circuit. By means of special mechanisms, direct current can be generated from alternating current. For this purpose, only so-called “rectifiers” are needed, which are built into the electrical circuit. Most electronic home appliances, such as computers, radios or TVs, use DC power for proper operation. However, the socket in the wall outputs AC power. The necessary rectifiers can be installed directly in the electrical appliance, but usually, an adapter or corresponding power supply is used, which converts the power.
- Alternating current
With alternating current, the direction, also called polarity, constantly changes in regular repetitions. The positive and the negative instantaneous values complement each other in such a way that the current is equal to zero in terms of time. If direct current and alternating current occur together in an electrical circuit, this is called mixed current. More AC is produced worldwide than in DC. The production of alternating current is comparatively simple, the direct current required for many electrical appliances can be easily converted or transformed. AC is used on a high frequency, especially in electromedicine and also in telecommunications. If you want to load a sensitive device, such as a smartphone, on a gasoline power generator, the generated power must be converted in any case. If this does not happen, the electrical appliance is likely to break down and can not be repaired due to the heavy overload in the electronic components.
Tutorial: Instructions for Using Digital Multimeters
With a portable power tester, you can easily see if any elements of your circuit are electrically connected. This is the so-called continuity test. On some devices, you will also receive visual and audible confirmation when the electrical current is flowing freely. For most multimeters, you will hear a distinct beep if the circuit under test is not live. In this case, stop the measurement and check all components for defects (eg cable breakage), check all solder joints for their quality and check the fuses. After troubleshooting, a repeated current check can be performed to inform you of the success and progress of your repair. Now switch on your multimeter and use the rotary switch to select the respective setting, for example, continuity test.
For most digital multimeters, a symbol that looks like a wave is shown here. Please refer to the details of the labelling of your current tester in the enclosed operating instructions as there may be differences in the representation between the various manufacturers. Above all, measuring instruments from abroad (Asia, America, Great Britain) may differ in the symbols on the device. Do not be afraid of a short circuit! If you have accidentally set a wrong measuring range, the multimeter warns you with a signal tone. If the test leads are electrically connected, the corresponding value appears in the display. In a simple continuity test, you will also be informed by a beep that electricity is flowing. You can easily perform this test by holding the two probes together – then read the display on your meter to see which indicator appears when power is flowing freely in the circuit. If no current flows, a “1” appears in the display – some devices also display “OL” (open loop).
Now you can go to troubleshooting. If your current tester does not have a continuity test function, you can still do it: Set the rotary switch on the front of the multimeter to “Measure resistance”, if necessary, the symbol Ω (ohm) can be seen here. Set the smallest possibility of resistance measurement. Your digital multimeter will now send a small amount of electrical current and measure whether it is also received at the other tip. If the value displayed on the display is very low or zero, you can assume that there is current flowing. You can always check the functionality by holding the two measuring tips together. If your current tester detects no current flow, the display will show “1” or “OL” (depending on the manufacturer).
Multimeter manual for voltage measurement on a battery
Connect the test leads to your digital multimeter as described above. Set the rotary switch to DC, it may also have a straight line or a V (for volts) at this point. Many current testers automatically switch between DC and AC, and at home, all home appliances are always DC powered. If your multimeter does not have automatic detection, set the range of voltage that you expect. If you select this value too low, you will be protected by the internal overload protection and will hear a warning tone. In this case, correct the manual value upwards. Now hold the red test lead to the positive pole of your battery or the circuit under test. Connect the black test lead to the respective negative pole.
For example, if you take a 9-volt block as the examination object, your digital multimeter should now display a value around 9 volts in the display. If you have swapped the two poles, you will see a negative value. An (inadvertent or intentional) reverse polarity will not damage your circuit or your multimeter. Only the value in the display is not correct. For further examples on the proper use of your multimeter, please refer to the manual. There are also many interesting video tutorials on the internet for using current multimeters. If necessary, search for a temperature measurement or transistor test instruction with the multimeter.