How to Measure a Time Delay With an Oscilloscope

An oscilloscope can be used to measure the time delay of an electrical signal.

Electricity is essential to modern day society since it allows mankind luxuries such as lighting, heating and cooking appliances. Electrical signals can take two main forms and these are direct current (DC) and alternating current (AC). An oscilloscope is an electrical device capable of measuring time-varying electrical signals. It consists of a main body with inputs, controls and a display to show the signal. Once the signal is on the screen, its time delay can be measured relatively easily.

Things You'll Need

• Oscilloscope
• Coaxial signal

Instructions

1. Use the coaxial cable to plug the signal into the oscilloscope. There are two inputs on an oscilloscope that are labelled "A" and "B." The signal can be plugged into either input. Switch on the selected input by pressing the "A" or "B" button.

2. Adjust the volts/division knob until part of the signal is displayed. This changes the vertical scale and the number of volts each square on the oscilloscope screen represents.

3. Adjust the time/division, the timebase, until a signal can be seen. The time/division modifies the horizontal scale and the amount of time each square on the screen represents. It should be adjusted so that two pulses of the signal are clear on the screen. If necessary, adjust the vertical gain so the signal is centered vertically, and adjust the trigger control so that the time delay is centered horizontally.

4. Count the number of squares that separate the end of the first signal and the onset of the second signal. Multiply this number by the time/division setting to obtain a value for the signal time delay. For example, if 6 squares are counted, and the time/division is 1 millisecond, then the time delay is 6 milliseconds.

References

• Electronics and Radio Today: How to Use an Oscilloscope