One importent function of the oscilloscope is to make voltage measurements. The scope os capable of measuring both DC and AC voltages.
Voltage is determinated by using vertical grids on the display.each square on the grid is called a divison.
Just as a voltmeter has a range switch , so does an oscilloscope . this switch selects volts per divison for example , at the 2 VOLTS/DIV position , one vertical divison repersents tow volts.
To make an AC voltage measurement, the coupling switch can be placed either the AC or DC position.
To make an ac measurement.
Step 1: click on the coupiling switch to move it to the GND position.
Step 2: move the horizental center line on the grid by adjusting the vertical position knob.
Step 3: connect the oscilloscope probe to a circuit that has 40 peak to peak AC,
· The ground is connected to a reference point of the circuit.
· The probe is connected to a location that has a diffrent potential than the reference point.
· Set the probe 10*/1* switch to the 1* position.
Step 4: click repeatedly on the VOLTS/DIV knob to set it the 10 VOLTS/DIV position.
· Click on the coupiling switch to move it from the GND to the AC position
The voltage measures 40 volts peak to peak because the vertical trace moves 4 divisitions with the range switch at 10 VOLTA/DIV. The sine wave appears with the positive alternation above the center line and the negitive alternation below the center line.
· Click on the coupiling switch twice to move it from the AC to the DC position.
Get it a fullscale reading. Deascreses the VOLTS/DIV setting to the 5 volts position.
Click on the VOLTS/DIV knob below to change the setting
The scope still measures 40 volts peak to peak , but at this VOLTS/DIV setting. The trace moves 8 seconds.
· The most accurate measurement is a achived when the VOLTS/DIV knob is reduced to lower positions untill as much of the screen is used as possible.
It is usually recommended to have the coupiling switch in the DC position because it can measure when the AC signal is riding on a DC voltage . for example , if the 40 volts peak to peak
Sawtooth voltage is combined with a positive 20 volts signal with the VOLTS/DIV switch in the 10 volt position, it would apper on the screen ,
When the coupiling switch is in the AC position ,it is only capable of measuring the AC sawtooth signal . ti is not capable of measuring the dc voltage . observe the signal when the coupiling switch is moved from DC to AC .
The largest voltage the oscilloscope in this learning object can measure is 400 volts.
· To make a higher reading, a times 10probe . labled 109, s available.
· It alternates(reduces) the incoming voltage by a factor of 10.
· By using the 10* probe on this sample, you can measure 400 volts. Some scopes have a VOLTS/DIV bracket at which the numbers on the knob are alinged when using this probe.
·
This display shows an 8 volt peak to peak sine wave when the probe switch is possible in the *1 position . by moving the switch to the *10 position ,the waveform is reduced by 1/10 its size.
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