summary
● Waveforms can be changed from one shape to another using various electronic circuits.
● The frequency domain concept holds that all periodic waveforms are made of sine waves.
● Periodic waveforms have the same waveshape in all cycles.
● Sine waves are the only waveform that cannot be distorted by RC, RL, or LC circuits.
● According to the frequency domain concept, waveforms consist of the fundamental frequency plus combinations of even or odd harmonics, or both.
● A square wave consists of the fundamental frequency plus an infinite number of odd harmonics.
● A sawtooth wave consists of the fundamental frequency plus even and odd harmonics crossing the zero reference line 180º out of phase with the fundamental.
● Periodic waveforms are measured from any point on a cycle to the same point on the next cycle.
● The pulse width is the length of the pulse.
● The duty cycle is the ratio of the pulse width to the period.
● The rise time of a pulse is the time it takes to fall from 10% to 90% of its maximum amplitude.
● The fall time of a pulse is the time it takes to fall from 90% to 10% of its maximum amplitude.
● Overshoot, undershoot, and ringing are undesirable in a circuit and exist because of imperfect circuits.
● An RC circuit can be used to change the shape of a complex waveform.
● If the output is taken across the resistor in an RC circuit, the circuit is called a differentiator.
● If the output is taken across the capacitor in an RC circuit, the circuit is called an integrator.
● Clipping circuits are used to square off the peaks of an applied signal or to keep an amplitude constant.
● Clamping circuits are used to clamp the top or bot- tom of a waveform to a DC voltage.
● A monostable multivibrator (one-shot multivibra- tor) produces one output pulse for each input pulse.
● Bistable multivibrators have two stable states and are called flip-flops.
● A Schmitt trigger is a special-purpose bistable multivibrator.