Electronics Demystified by Stan Gibilisco

Author:Stan Gibilisco
Language: eng
Format: epub, pdf
Tags: Electronics Demystified
Publisher: McGraw-Hill Education
Published: 2012-02-13T16:00:00+00:00

= 10 log10 (1/15)

= 10 log10 0.06667

= 10 × (−1.176)

= −11.76dB

Because we’re told the attenuation factor is exact, we can leave this figure as it is. An engineer would probably round it off to −11.8 dB or maybe even to −12dB. That is the gain of the attenuator. We can also say that the circuit produces 11.8 dB or 12 dB of power loss.

Basic Amplifier Circuits

In general, amplifiers must use active components, such as transistors or ICs. A simple AC transformer can increase the deliverable current or voltage if the input and output impedances differ. But it cannot produce an output signal that has more power than the input signal, nor can it increase the current or voltage if the input and output impedances are the same.

GENERIC BIPOLAR AMPLIFIER

A generic NPN bipolar-transistor amplifier is shown in Fig. 7-1. The input signal passes through a capacitor to the base. Resistors provide bias. In this amplifier, the capacitors must have values large enough to allow the AC signal to pass with ease. But they should not be much larger than the minimum necessary for this purpose. The ideal capacitance values depend on the design frequency of the amplifier, and also on the impedances at the input and output. In general, as the frequency and/or circuit impedance increase, less capacitance is needed. Resistor values depend on the input and output impedances.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.