This tutorial will show you how to use a digital multimeter (DMM), We will be using the SparkFun VCL throughout the tutorial, but these methods should. Make Magazine's Bre & Joey Grand on how to use a multimeter You can always use a resistance-tester (ohmmeter) to figure out if something. Otherwise reverse movement of the pointer can damage an analog multimeter. It is therefore necessary to use each type to its best advantage. Digital Multimeter.
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Perhaps the most important tool you'll use in troubleshooting auto electrical systems Basic multimeters measures voltage, current and resistance, while. In this post we're going to show you how to use a multimeter. This post is mostly addressed for beginners who are starting out in electronics and.  SAFETY PRECAUTIONS. This instruction manual explains how to use your new digital multimeter PS8a safely, Before use, please read this manual.
To measure the voltage drop across the resistor: You just have to place the red probe in one lead of the resistor and the black probe on the other lead of the resistor. The red probe should be connected to the part that the current is coming from. Measuring Current To measure current you need to bear in mind that components in series share a current. So, you need to connect your multimeter in series with your circuit.
The multimeter acts as if it was a wire in your circuit. In the example below, the same circuit of the previous example is used. The multimeter is part of the circuit. Measuring Resistance Plug the red probe into the right port and turn the selection knob to the resistance section. Then, connect the probes to the resistor leads. Checking Continuity Most multimeters provide a feature that allows you to test the continuity of your circuit. A True RMS responding multimeter on the other hand will meet its specified accuracy on AC volts and current with any waveform type up to a specified crest factor ; RMS performance is sometimes claimed for meters which report accurate RMS readings only at certain frequencies usually low and with certain waveforms essentially always sine waves.
A meter's AC voltage and current accuracy may have different specifications at different frequencies. Sensitivity and input impedance[ edit ] When used for measuring voltage, the input impedance of the multimeter must be very high compared to the impedance of the circuit being measured; otherwise circuit operation may be changed, and the reading will also be inaccurate.
Meters with electronic amplifiers all digital multimeters and some analog meters have a fixed input impedance that is high enough not to disturb most circuits. This is often either one or ten megohms ; the standardization of the input resistance allows the use of external high-resistance probes which form a voltage divider with the input resistance to extend voltage range up to tens of thousands of volts.
The impedance of the meter varies depending on the basic sensitivity of the meter movement and the range which is selected. On every range, at full-scale voltage of the range, the full current required to deflect the meter movement is taken from the circuit under test.
Lower sensitivity meter movements are acceptable for testing in circuits where source impedances are low compared to the meter impedance, for example, power circuits ; these meters are more rugged mechanically.
Some measurements in signal circuits require higher sensitivity movements so as not to load the circuit under test with the meter impedance.
Multimeters designed for mains "electrical" use instead of general electronics engineering use will typically forego the microamps current ranges. Measurement of low resistance requires lead resistance measured by touching the test probes together to be subtracted for best accuracy. This can be done with the "delta", "zero", or "null" feature of many digital multimeters.
Contact pressure to the device under test and cleanliness of the surfaces can affect measurements of very low resistances. Some meters offer a four wire test where two probes supply the source voltage and the others take measurement.
Using a very high impedance allows for very low voltage drop in the probes and resistance of the source probes is ignored resulting in very accurate results. Burden voltage[ edit ] Every inline series-connected ammeter, including a multimeter in a current range, has a certain resistance. Most multimeters inherently measure voltage, and pass a current to be measured through a shunt resistance , measuring the voltage developed across it.
The voltage drop is known as the burden voltage, specified in volts per ampere. The value can change depending on the range the meter sets, since different ranges usually use different shunt resistors.
To check for its effect on accuracy and on external circuit operation the meter can be switched to different ranges; the current reading should be the same and circuit operation should not be affected if burden voltage is not a problem. If this voltage is significant it can be reduced also reducing the inherent accuracy and precision of the measurement by using a higher current range.
Alternating current sensing[ edit ] Since the basic indicator system in either an analog or digital meter responds to DC only, a multimeter includes an AC to DC conversion circuit for making alternating current measurements. Basic meters utilize a rectifier circuit to measure the average or peak absolute value of the voltage, but are calibrated to show the calculated root mean square RMS value for a sinusoidal waveform ; this will give correct readings for alternating current as used in power distribution.
User guides for some such meters give correction factors for some simple non- sinusoidal waveforms , to allow the correct root mean square RMS equivalent value to be calculated.
More expensive multimeters include an AC to DC converter that measures the true RMS value of the waveform within certain limits; the user manual for the meter may indicate the limits of the crest factor and frequency for which the meter calibration is valid. RMS sensing is necessary for measurements on non-sinusoidal periodic waveforms, such as found in audio signals and variable-frequency drives.
Modern multimeters are often digital due to their accuracy, durability and extra features. In a digital multimeter the signal under test is converted to a voltage and an amplifier with electronically controlled gain preconditions the signal. A digital multimeter displays the quantity measured as a number, which eliminates parallax errors.
Modern digital multimeters may have an embedded computer , which provides a wealth of convenience features. Measurement enhancements available include: Auto-ranging, which selects the correct range for the quantity under test so that the most significant digits are shown. For example, a four-digit multimeter would automatically select an appropriate range to display Auto-ranging meters usually include a facility to hold the meter to a particular range, because a measurement that causes frequent range changes can be distracting to the user.
Auto-polarity for direct-current readings, shows if the applied voltage is positive agrees with meter lead labels or negative opposite polarity to meter leads. Sample and hold , which will latch the most recent reading for examination after the instrument is removed from the circuit under test.
Current-limited tests for voltage drop across semi conductor junctions. While not a replacement for a proper transistor tester , and most certainly not for a swept curve tracer type, this facilitates testing diodes and a variety of transistor types. A low-bandwidth oscilloscope. Simple data acquisition features to record maximum and minimum readings over a given period, or to take a number of samples at fixed intervals.
The interface allows the computer to record measurements as they are made. Topics include Hindi stories, Ayurveda and health.
How to Use Multimeter. About how to use a multimeter.
Read this owner' s manual thoroughly before use. Alligator clips are often used to firmly grip wiring or contacts for hands- free safe. Txt or read online for free. After watching this video you will be able to- - Test trans. A multimeter is an instrument used to check for AC or DC voltages, resistance and continuity of electrical components, and small amounts of current in circuits.
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This tutorial will show you how to use a digital multimeter DMM ,.