Digital Electronics Ch. 4 "Signal Processing and Conditioning with Two-Terminal Nonlinear Devices"

Diodes, Transfer characteristics, and Rectifiers

Transfer Characteristics of a Circuit

Describes the relationship between the input signal and the output signal. (V_in vs. V_out)

Clipping and Limiting Circuits

A term used interchangeably to mean a circuit that limits (or "clips") part of an input signal above or below a certain voltage threshold using diodes and sometimes reference voltages. It alters the waveform shape by removing portions that exceed specific voltage levels.

Rectifier

One or more diodes appear in series between the input and output ports, and the output is applied to a passive load element. The primary function is to change an AC input voltage into a DC voltage.

Half-Wave Rectifier

Using one diode, outputs positive values 0 < V_in < (V_max - V_f) or negative values 0 > V_in > (V_min + V_f). Output is pulsating DC, not smooth.

Bridge Rectifier

Using four diodes, this rectifier allows for current to flow in for both positive and negative values of V_in but always in the positive i_load direction.

Half-Wave Rectifier Power Supply

Includes a diode and a capacitor. A complete circuit used to deliver DC power. Much smoother DC than original but still has a ripple.

Bridge Rectifier Power Supply

Includes four diodes and a capacitor, has usable DC power, and often includes voltage regulation.

Ripple Voltage / Factor

The bumpiness of the output waveform. Ideally, the ripple should be small. A high ripple means poor voltage regulation. It should be minimized for quality DC supplies.

Precision Rectifier

A diode-drop problem can be overcome by adding one or more diodes to an op-amp. An Op-Amp can effectively bypass the 0.7 V needed to turn on the diode. Can be half-wave or full wave.