Experiments with oscilloscope - part 2

Experiments with oscilloscope

METHODOLOGY
Calibrate the oscilloscope
Before using oscilloscope for the practical we must calibrate the oscilloscope.it is essential step in this setup. Firstly we were calibrated the oscilloscope. Calibration is the comparison of a measurement against an equal or better standard. A standard measurement can find in OCR, it can be considered as a reference.

Step 01
Firstly, we sat all the controls on oscilloscope to normal positions.

Step 02
Then we turned ON the oscilloscope.

Step 03
There was a slanted in line on the oscilloscope screen and we used screwdriver and slightly tiled trace rotation (knob in hole) and got the line in straight.

Step 04
After that we adjusted VOLTS/DIV to 1 milli volts near to the CH 1 (mode in CH1) and TIME/DIV 0.5 milliseconds

Step 05
We sat the trigger switch to auto.

Step 06

We connected the probe to CH 1 in oscilloscope and CAL terminal in left side bottom corner. There is mentioned 2Vp – p & 1 kHz. (See Figure 3: inscription in CAL termination) It’s mean the oscilloscope must be calibrated so that the value of the peak to peak is 2Volts (Y axis) and frequency is 1 kHz (X axis).
Step 07
We used VAR in VOLTS/DIV change the distance up and down on wave in Y position. (We sat it to 2 deviations or 2 Squares in peak to peak on Y axis)

We used VAR in TIME/DIV change the distance horizontally on wave in X position. (We sat it to 2 deviations or 2 Squares on X axis). Then 0.5ms+0.5ms = 1ms, frequency = 1/T = 1 kHz

Step 08

We adjusted INTEN (intensity) and FOCOUS knobs to get clear view of wave in the oscilloscope screen.

Measurement of DC Voltages
After calibrating the oscilloscope, we measured different voltages in power supply using oscilloscope and multimeter.
We connected probe into CH 1 in oscilloscope. (Its circuit connection like this, power supply ground to probe ground and probe positive to power supply positive)
Used vertical position knob on CH 1 to move the trace onto the center line of the oscilloscope screen.

After that we Sat CH 1 coupling to DC.

After that we sat three different DC Voltages and take down the readings with uncertainty values.

We got a measurements with Multimeter parallel with three different voltages and took down the readings.

AC Measurements
Firstly we connected a function/signal generator to a CH 1 of the oscilloscope.
Then we sat the function generator to 1 kHz. (Used 1k button and sin wave button)
After that we sat TIME/DIV in CH1 into 1ms and VOLTS/DIV into 5V.
After that adjusted vertical and horizontal positions to obtain clear wave form and get the readings.
We did for the two different frequencies.

We calculated RMS value of the voltage and the frequency.so calculation we need to solve below equations for get values.

𝐴(𝐴𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒)=√2𝑉𝑟𝑚𝑠
We got the A (amplitude) by using peak to peak deviations (squares) and multiply it with voltage scale.
(Δ𝑓f)2= (Δ𝑡t)2 (d𝑓dt)2= Δ(1t)2

Δf=(1𝑡2)(Δt)

AC & DC Coupling
Oscilloscope CH 1 coupled to the DC
Then we sat the function generator to 10 kHz.

After that turned ON the offset voltage on the function generator, and changed the offset up & down.

In next tutorial we will discuss about analyzing part.
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Lecturer : Laahiru C.Fernando.