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ANDAYA, ROBERT ANDREY R. NEC_2107 – ECE
August 17, 2020 Engr. Meldanette B. Austria Activity 1. Familiarization of Electronic Instruments and Equipment ELECTRONIC EQUIPMENT
- Oscilloscope What is an oscilloscope? Picture of the actual Digital (Tektronix Brand) and Analog Dual Oscilloscope Label the parts of each Oscilloscope and briefly discuss each functions Show an example of a graph projected on the screen of the oscilloscope and label each part. How is it its calibration (each)?
- Function Generator Picture of the actual Analog and Digital Label the parts of each and briefly discuss each functions
- Multimeter and DVOM Actual picture Label the parts of each briefly discuss each functions How is its calibration? (Each)
1. Oscilloscope Oscilloscope Display signals in a graphical format on a pair of axes, generally with Y as the voltage and X as the time. This format offers a very powerful method to understand the shape of a signal, determine what is going on in an electronic circuit, and monitor its performance or track down problems. Digital Oscilloscope Digital Oscilloscope parts and description 1. On/Off. Do not use the wall plug as an on/off switch. Good switches help to control electrical transients which can be harmful to sensitive circuit components. 2. Intensity. Adjust the brightness of the trace until you can just see all the details of the waveform. If the trace is too bright you will not get the best data, your eyes will get very tired, and you could damage the scope. 3. Focus. Rotate this button until the trace is sharp.
- Channel select. Most oscilloscopes are dual trace. This means that they can display two signals at once, which is why there are two signal ports and two sensitivity controls.
- Signal ports. There is one signal port for each channel. It is a BNC connector for this oscilloscope.
- Sensitivity calibration. This knob is used to change the vertical scale. If it is not turned all the way clockwise, the scope will be uncalibrated and your data will be worthless. Check this knob frequently as you take data.
- Sensitivity. This determines the vertical scale. It is read in the left hand white window. The units are volts/division.
- Vertical positio n. This knob controls the vertical position of the trace. You will find it very convenient when you are setting or reading voltages.
- AC/DC select. When this is set to "AC" the DC part of the signal is filtered out by a capacitor placed in series between the signal input and the scope. When the selector is set to "ground", the beam will move to zero volts. When the selector is set to "DC", the entire signal will be displayed on the scope. Analog Oscilloscope
Analog Oscilloscope parts and description Intensity and focus controls, which allow the users to adjust the brightness, size, clarity, and focus of the spot or trace on the CRT screen caused by the electron beam Position controls (vertical and horizontal), which allow adjusting voltages that control the position of the trace on the CRT screen and control the position and movement of the electron beam coming from the opposite end of the tube and striking the back of the screen. The horizontal sweep frequency controls are used to control the linear trace speed and repetition rate of the horizontal trace of the electron beam across the CRT screen. The sweep frequency controls —horizontal time variable, “VAR,” and horizontal sec/div (seconds per division)-adjust the frequency of the horizontal sweep circuitry in the oscilloscope. This controls the number of times per second the beam is traced horizontally across the CRT screen. The horizontal frequency control(s) allows us to view signals of different frequencies. Vertical section is where signals to be analyzed are input into the scope, amplified, or attenuated, as needed for proper viewing. Key elements in this section are the vertical input jack(s) (sometimes called Y input jacks), and the vertical attenuator and vertical amplifier, with related controls. When the scope is a single-trace scope, there is only one vertical input jack. When a dual-trace scope is involved, there are two vertical in- put jacks. Horizontal section allows control of voltages and signals applied to the horizontal deflection plates. We have briefly discussed some of the important horizontal deflection
Graph Projected in Oscilloscope Calibration of Oscilloscope An oscilloscope is an incredibly useful tool to have on your electronics workbench. Unfortunately, oscilloscopes are also expensive, costing at least a few hundred dollars. So most electronic hobbyists get by without one. But if you have one, you must first verify the settings of some key controls on your oscilloscope before you take a measurement. The exact steps you need to follow to set up your oscilloscope vary depending on the exact type and model of your scope, so be sure to read the instruction manual that came with your scope. But the general steps should be as follows:
- Examine all the controls on your scope and set them to normal positions.
- For most scopes, all rotating dials should be centered, all pushbuttons should be out, the VOLTS/DIV control to 1.
This sets the scope to display one volt per vertical division. Depending on the signal you’re displaying, you may need to increase or decrease this setting, but one volt and all slide switches and paddle switches should be up.
- Turn your oscilloscope on. It it’s the old-fashioned CRT kind, give it a minute or two to warm up.
- Set is a good starting point.
- Set the TIME/DIV control to 1 ms. This control determines the time interval represented by each horizontal division on the display. Try turning this dial to its slowest setting. Then, turn the dial one notch at a time and watch the dot speed up until it becomes a solid line.
- Set the Trigger switch to auto. The Auto position enables the oscilloscope to stabilize the trace on a common trigger point in the waveform. If the trigger mode isn’t set to Auto, the waveform may drift across the screen, making it difficult to watch.
- Connect a probe to the input connector. If your scope has more than one input connector, connect the probe to the one labeled A. Oscilloscope probes include a probe point, which you connect to the input signal and a separate ground lead. The ground lead usually has an alligator clip. When testing a circuit, this clip can be connected to any common ground point within the circuit. In some probes, the ground lead is detachable, so you can remove it when it isn’t needed.
- Touch the end of the probe to the scope’s calibration terminal. This terminal provides a sample square wave that you can use to calibrate the scope’s display. Some scopes have two calibration terminals, labeled 0.2 V and 2 V. If your scope has two terminals, touch the probe to the 2 V terminal. For calibrating, it’s best to use an alligator clip test probe. If your test probe has a pointy tip instead of an alligator clip, you can usually push the tip through the little hole in the
Digital function generator Function generator parts and description
1. Over range led. Lights if you apply a frequency above specified limits to the EXT COUNTER INPUT connector. It also lights if the gate time is too slow for the incoming signal. 2. Gate led. Lights when the frequency counter is making a measurement. The LED will blink when the counter updates the display. 3. Counter readout. This is a five-digit display that shows frequency counter
measurements. The decimal point is automatically placed in the appropriate position, depending on the measurement and resolution.
4. Multiplier led. Indicate the frequency multiplication factor of the function generator outputs. The 10-1M LED indicates a factor from 10 through 106. You should use the 10-1M LED with the counter readout and FREQUENCY Range LEDs. The 1 and 0.1 LEDs provide accurate indication for the two lowest frequency ranges. For example, if the FREQUENCY dial is set on 2.6 and the 1 LED is lighted, the function generator output frequency is 2.6 Hz. 5. Frequency range led. Indicate the range (either MHz or kHz) of the reading shown on the counter readout. These LEDs also indicate the frequency range of the function generator output. For example, if the FREQUENCY dial is set on 9, the 10-1M LED is lighted, the kHz LED is lighted, and the counter readout shows .090, then the function generator output frequency is 0.090 kHz = 90 Hz. 6. Sec led. Lights when the frequency counter is in PERIOD mode. The counter readout does not show frequency in hertz, but period in seconds. For example, if the FREQUENCY dial is set at 4, the 1 multiplier LED is lighted, and the SEC LED is lighted, the counter readout displays a value close to 0.250. This indicates the generator output period is .25 s (the frequency is 4 Hz). 7. Multiplier buttons. Set the frequency range. The left button raises the range by a power of ten and the right button lowers the range by a power of ten. For example, if the FREQUENCY dial is set to 4.7 and the output is set to kHz, when you press the left multiplier button the output frequency will jump from 4.7 X 103 Hz (4.7 kHz) to 4.7 X 104 Hz (47 kHz). 8. Function buttons. Select the type of waveform generated: sine, triangle, or square. 9. Symmetry Buttons. Select either positive pulse/ramp or negative pulse/ramp (see Table
VP-P. This control is used with the AMPLITUDE control to set the voltage level of the MAIN OUT signal.
16. Amplitude knob. Adjusts the voltage within the presently selected range. This control is used with the MAIN control to set the voltage level of the MAIN OUT signal. 17. Dc offset knob. Sets the DC level (and therefore the polarity) of the MAIN OUT signal. This knob has no effect until you pull it out. 18. Sweep width knob. Adjusts the range of frequencies that are traversed by each sweep. 19. Sweep out bnc. This connector sends sweep signals that you can adjust with the sweep controls. You can use a sweep signal to synchronize an external device such as an oscilloscope. 20. Main out bnc. This connector sends sine, triangle, square, and positive and negative pulse/ramp signals. 21. Sync out bnc. This connector sends TTL trigger signals. Amplitude and DC offset adjustments do not affect TTL trigger output. 22. Ext counter input bnc. This connector can accept external signals with frequencies between 1 Hz and 100 MHz 23. Freq Fine ADJ knob. Allows small adjustments in output frequency. 24. Dial. Determines the frequency of the function generator output, within the range set by the multiplier buttons. 25. Power switch. Toggles instrument power on and off.
3. Multimeter and DVOM Multimeter DVOM Parts and Definition of multimeter Pointer or Needle – indicates the values read from the scale Scale – shows the value of what is being measured Dial/Infinity Knob – points the needle to the 0 at the left side of the scale Zero Ohm Adjuster – adjusts the needle to the right side of the scale Range Selector Knob – allows changing the function and scale Range – allows more accurate measurement for small values
Step 1 Set the multimeter to the highest resistance range by turning the dial to the highest "ohm" setting. Step 2 Touch the test probes of your digital multimeter together. The digital display of the multimeter should read "0 ohms." Step 3 Press the calibration knob until the display reads "0" on the digital multimeter if you don't see "0 ohms" initially.
