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# EEE project.pptx

28 Mar 2023
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### EEE project.pptx

1. DIGITAL MULTIMETER A digital multimeter, or DMM, is a device that can measure multiple electrical values, such as voltage, current, resistance, frequency, capacity, or temperature. It has probes, clamps, or leads that connect to the device under test. It shows the measured values as numerical values on a digital display. Some digital multimeters can select the measurement range automatically. It is a standard diagnostic tool for technicians and electrical engineers.
2. Why are digital multimeters used? • A DMM is primarily used to verify one of the three factors of Ohm’s Law voltage (volts), current (amps) and resistance (ohms). This simple equation, expressed below, is commonly used by electrical engineers during diagnostic testing. • V = I x R where V = voltage, I = current, R = resistance • Engineers in the lab and in the field also use digital multimeters to verify the state of a system or circuit for safety purposes. For instance, voltages in excess of 42V or currents in excess of 10 mA can provide painful shocks, and in some cases, be lethal. Resistances are also rated for certain powers (watts) and can get hot when driving higher currents and voltages. Digital multimeters essentially help engineers verify that a device under test is safe to work on.
3. Types of digital multimeters • General purpose digital multimeter • Handheld digital multimeter • Advanced digital multimeter • Compact digital multimeter
4. How to use a digital multimeter A digital multimeter is very easy to set up and use to run tests in the lab. Simply follow the six steps below to set up your digital multimeter and start measuring a device under test (DUT). 1. Inspect your digital multimeter and DUT for signs of physical damage. 2. Insert the appropriate probes into the DMM inputs (the probes and inputs are typically color coded for ease of use). 3. Set your DMM to resistance, voltage or current mode, depending on what you’re measuring.
5. 4. Test that your DMM is working correctly with a known voltage source. 5. Hold the tip of the probes or clamps to the positive and negative terminals of the DUT to make your measurements. 6. As you’re working, watch the DMM’s display screen for safety warnings.
6. DIGITAL STORAGE OSCILLOSCOPE A digital storage oscilloscope (DSO) is an electronic test instrument that is used to measure and display electrical signals. Unlike traditional analog oscilloscopes that use a CRT (cathode-ray tube) display, a DSO uses digital signal processing to capture, store, and display waveforms on a digital screen. A DSO can capture and store waveforms in its memory, allowing you to view and analyze them at a later time. This makes it ideal for applications that require detailed analysis of complex signals, such as digital communication systems, power electronics, and control systems.
7. Why are digital storage oscilloscopes used? An oscilloscope measures and displays voltage signals on a time-versus-voltage graph. In most applications the graph shows how the signal changes over time: the vertical (Y) axis represents voltage, and the horizontal (X) axis represents time. • This simple graph can tell you many things about a signal: • View the signal for anomalies • Calculate the frequency of an oscillating signal • Tell if a malfunctioning component is distorting the signal • Tell how much of the signal is noise and whether the noise is changing with time
8. How to use a digital storage oscilloscopes? 1. Connect the probe 2. Adjust the vertical scale 3. Adjust the horizontal scale 4. Adjust the trigger: 5. Capture the waveform 6. Analyze the waveform 7. Save and export data
9. Digital multimeter vs. oscilloscope A digital multimeter allows you to read the voltage at any one moment in time, but oscilloscopes show how the voltage changes over time by graphically displaying a waveform. Oscilloscopes are often used over digital multimeters when troubleshooting more complex circuits. Used to: Circuit type: Oscilloscope Circuit type: Oscilloscope Measure how the voltage changes over time. Complex Circuits it type: Digital multimeter Read the voltage at any one moment in time. Simple Circuits
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