Pulses Tutorial

• The voltage rises very rapidly from zero to its maximum value.
• It stays steady at the maximum value for a time.
• It then falls very rapidly back to zero.
• The duration of a pulse can be anywhere from a very long time (days) to a very short time (picoseconds or less).
• Pulses do not rise and fall instantaneously but take time (which may be very short).
• They are called the RISE and FALL times.

If pulses occur one after another they are called a PULSE TRAIN.

The duration time of a pulse is called the MARK.

The time between pulses is called the SPACE.

The relative times are expressed as the MARK/SPACE RATIO.

Mark/space ratios can vary.

Fig. 3 has a 50:50 mark/space ratio.

This is a special case called a SQUARE WAVE.

Fig. 4 is about 1:10

Fig. 5 is about 10:1

Note that the last three waveforms are of the same frequency. All the pulses start at the same instant.