Learn how to use multimeter symbols efficiently for electric measurements. Unlock the secrets and techniques of voltage, current, resistance, and greater. Elevate your electrical troubleshooting abilities with this complete exploration.
In the early days of electricity, laboratory employees might use a voltmeter to measure voltage and an ammeter (galvanometer) to measure electric current in a circuit. They could then compute resistance from there.
The AVOmeter, created in 1920 by British postal engineer Donald Macadie, measured all three values (A = amps, V = volts, and O = ohms). Not too long afterward, field electricians obtained slightly portable copies of this innovation.
Modern multimeters are more advanced and capable of performing several other tests in addition to performing the same tasks as the AVOmeter. A multimeter can detect the temperature of wires, identify between alternating and direct current, and determine if a diode or capacitor is operating, depending on the type. Symbols are placed around a dial to represent different functions.
Multimeters found in hardware stores are simpler than those found at electronics supply outlets since homeowners performing do-it-yourself electrical work don’t require the same capabilities as electronics specialists. Nevertheless, it might be challenging to interpret the symbols. This is a list of the terminology and symbols related to electricity that you may find on a simple home multimeter, along with their definitions.
A Multimeter: What Is It?
A multimeter is essentially an electrical instrument that measures resistance, voltage, current, and, in certain versions, temperature. They may also be known as “multi-testers,” as you may have heard.
These multipurpose devices include HVAC (heating, ventilation, and air conditioning) tools of industrial quality, as well as general-purpose household appliances and automotive-oriented models. Multimeters come in two primary varieties: analog and digital. They both measure voltage in volts, resistance in ohms, and current in amps.
Multimeter Symbols You Should Understand
The voltage
Multimeters must show several voltage symbols because they are capable of measuring both direct current (DC) and alternating current (AC) voltage. The AC voltage on certain earlier devices is denoted as VAC. Manufacturers now frequently indicate AC voltage with a wavy line placed over the V.
It is customary to draw a solid line over a dotted line, covering the V, to represent DC voltage. Set the dial to millivolts (mV), which is one thousandth of a volt, to obtain voltage readings.
A “V” with a wavy line across it represents AC voltage.
One solid over a dotted one to form a “V” represents DC voltage.
“mV” with a single wavy line or two lines over it—one dotted and the other solid—represents millivolts, either AC or DC.
Current
Current can be either AC or DC, much like voltage. Current has the sign A because its unit is ampères, or amps.
- A wavy line over the letter “A” indicates AC current.
- “A” with two solid and dotted lines above it equals DC current.
- Milliamperes is mA.
- Microamps, represented by the Greek symbol mu (µA), are millionths of an amp.
Resistance
A multimeter works by passing a little electric current across the circuit to measure resistance. It is represented by mega (Ω) . There are no lines above this symbol because meters cannot tell the difference between AC and DC resistance.
The mega ohm (one million ohms) and kilohm (1,000 ohms) scales, denoted as kΩ and MΩ, respectively, are available on meters that provide range selection choices.
- Ohms are represented by Ω.
- Kilohms are represented as kΩ.
- Mega ohms is equal to MΩ.
Continuity
Check for a break in an electrical circuit with a multimeter. There are just two results when the resistance is measured by the meter. The meter indicates that the circuit is either broken (open), in which case it reads infinite resistance, or closed (closed), in which case it reads 0 (or very near to it).
Certain meters detect continuity and emit a beep since there are only two options. A sequence of progressively larger left-facing brackets on the dial settings indicate this function; they resemble a flipped version of a laptop’s wifi reception sign.
Tests for Diodes and Capacitors
Compared to electricians or homeowners, electronics technicians are more likely to use the capacitance and diode tests. However, it’s helpful to understand the meaning of the symbols if your meter has these features.
The diode test function resembles an arrow that points from the outside of a plus sign to its centre. The meter will indicate whether or not a diode—a typical electronics component that converts AC current into DC current—is functioning when this function is selected.
The capacitance function looks as a bracket oriented rightward next to a vertical line. A line that runs horizontally crosses both. Electronic devices called capacitors hold charge, which may be measured using a meter.
The circuit wires’ temperature is determined by the temperature function. A thermometer is used to indicate it.
Buttons and Jacks
Every multimeter comes with two leads: a red and a black lead. There are meters with three or four jacks. Depending on what you’re testing, different jacks need to be plugged in for the leads.
- The only black jack is the common jack, or COM. This jack is where the black lead is always plugged in.
- In the event that you are monitoring high current up to 10 amps, jack A is where the red lead goes.
- If the meter has just three jacks, then mAVΩ is the jack for all other readings, such as temperature, voltage, resistance, and sensitive current measures.
- If the meter has four jacks, the jack for sensitive current measurements (less than one amp) is mAµA.
- The jack for all other measurements—aside from current—is VΩ.
Usually, there are two buttons—one on the left and one on the right—at the top of the meter display, above the dial.
Change. Some dial locations may have two purposes assigned by manufacturers to conserve space. Pressing the shift button, which is often also yellow and may or may not be marked, allows you to access the function indicated in yellow.
Pause. The current reading is frozen for future reference when this button is pressed.
Range: Manual vs. Auto
There should be many range settings on an analog multimeter that is older and has a needle. The meter could not be utilized for sensitive measurements if it just had a wide range since the needle would rarely deflect. In contrast, any reading that exceeded the meter’s limited range—regardless of magnitude—would cause the needle to deflect to its maximum.
The majority of multimeters on the market today are digital, having first been launched in the 1970s with LED displays. Some still include dials for selecting the range. However, the meter is choosing the range on its own more and more.
Auto-range multimeters can be more useful than those with manual range settings since they lack range settings, which can take up to 18 dial positions.
Conclusion to multimeter symbols
In the area of electrical diagnostics, interpreting multimeter symbols becomes an effective talent. Our guide has illuminated the importance at the back of these symbols, empowering you to confidently navigate voltage, present day, resistance, and past. As you embark for your adventure with multimeters, the information received will function as a treasured asset, transforming your capability to troubleshoot, degree, and recognize the elaborate workings of electrical structures. Equip your self with this newfound knowledge and embark on a greater confident and informed technique to electric measurements.
