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THE OSCILLOSCOPE

- shows graphically the behavior of an electrical signal

- qualitative measurement type rather than quantitative

- low precision for both voltage and frequency

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WORKING PRINCIPLE OF OSCILLOSCOPE

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WORKING PRINCIPLE OF OSCILLOSCOPE

- Y AXIS - Vertical = Voltage:

V/Div; mV/Div

- X AXIS - Horizontal =TIME BASE:

s/Div; ms/Div; µs/Div; ns/Div

- The vertical axis is driven by the input signal

- The horizontal one by the internal time base

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WORKING PRINCIPLE OF OSCILLOSCOPE

Example: 1V/Div (2V peak-to-peak); 10 µs/Div (25 kHz).

- Without input signal : flat line.

- Switching the the gain - change of divisions in Y axis.

- Switching the time base - change of frequency

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OSCILLOSCOPE - TRIGGER

!! every scan draws a new trace !!

result on the screen

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Trigger event: - input signal crosses the trigger level - detection by voltage comparator - rising (positive) OR falling (negative) edge - trigger starts new scan

For constantly repeated waves: 1) Identical trigger event restarts a new scan 2) New picture retrace exactly the previous shape

Result : stable waveform on the grid

(Signal is : triggered ; locked ; coupled ; hooked up)

OSCILLOSCOPE - TRIGGER

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Trigger-setting

1)Select the edge - positive or negative.

2) Set the trigger voltage level.

OSCILLOSCOPE - TRIGGER

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SINGLE - one shot mode- the scan starts only once at first trigger event - for next scan new start needed (manually)

NORMAL - scan restarts only on trigger event - at the end waiting for next event - with no trigger events - not any trace

AUTO - scan restarts automatically at each end of scan - trace is always shown without input signal- small signal does generate “trigger”- sliding waveforms

OSCILLOSCOPE - TRIGGER

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DIGITAL OSCILLOSCOPE

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DIGITAL OSCILLOSCOPE Tektronix

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OSCILLOSCOPE: Mind the ground connection !!!!

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DIGITAL MULTIMETER METEX

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DIGITAL MULTIMETER METEX

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POWER SUPPLY: MIND THE TERMINALS !!

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EXPERIMENTAL BOARD

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EXPERIMENTAL BOARD: DIODE RECTIFIER

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