Electronic Circuit Analysis and Design 1: feedback Amplifiers and Oscillators

Feedback

Feedback

Process of the output signal (voltage or curnet) is returned to the input

Gain

Part of feedback amplifier that tells how nuch an amplifier amplifies a signal. A ratio of output/input

Distortion

Part of feedback amplifier that tell about the disturbance, noise,unwanted variation at the output signal

Impedance

Part of feedback amplifier that tells effective resistance; combined effect of ohmic resistnace and ohmic reactance.

Impedance

Part of feedback amplifier that tells effective resistance; combined effect of ohmic resistnace and ohmic reactance.

Positive Feedback

Also known as regenerative feedback, feedback signal is unphased with the inout signal. It does have overall voltage gain. It does have higher quality factor, narrow bandidth, and unstable gain. Oscillator uses positive feedback.

Negative Feedback

Also known as degenerative feedback, feedback signal that is out of phase by 180 degrees with the input signal. It does have stabilized voltage gain, lower noise, lower distortion,wider feedback, and amplifiers since there is an output to meet. It is in linear operation and for control system uses.

Gain Desensitization

One advantages of negative feedback. Output signal becomes less sensitive to small variations from the inout signal and from variations in temperature

Improved Frequency Response

One of the advantages of negative feedback. A gain is decreased, the range of working frequencies increases.

Reduction of Undesirables

One of the advantages of negative feedback. Distortions due to the nonlinear propeties of the devices and noise is made as small possible

i/O Impedance Modification

One advantage of negative feedback. Impedance can be modified to achieve maximum power transfer between devices.

Reduced Gain

Disadvantage of negative feedback. Overall gain is reduced.

Bad at Higher Frequency

One of disadvantage of negative feedback. At higher frequencies, your amplifier may turn into a oscillator.

Oscillator

Circuit that generates alternating current at a frequency determined by the values of its components and provides a constantly varying output signals. Produced by using a positive fedback with an amplifier.

Colpitts Oscillator

It does have 2 capacitor in parallel. Used in frequency range of 100kHz to 500kHz.

Hartley Oscillator

There is 2 inductors in parallel

Clapp Oscillator

There is 3 capacitor

Armstrong Oscillator

There is a transformer.

Phase-Shift Oscillator

Used for low frequency

Wein-Bridge Oscillator

Widely used oscillator circuit. Operates between 5hz to 500kHz.

Crystal Oscillator

It operates at series or parallel resonance. Does have High Q factr resulting in accurate resonance frequency.

Rochelle Salt

Greatest Piezoelectric yet weakest

Tourmaline

Strongest piezoelectric yet most expensive

Quartz

midway between Rochelle and Tourmaline, most common, least expensive.

Multivibrator

It is a relaxation oscillator circuit that produces oscillation between high and low level states at the output. It uses two active components (trransistor) that are coupled such that one of the components is conducting, while the other is cut-off

Bistable Multivibrator

A switching circuit with two stable output states. Also caled flip-flop. The output changes state when receives a valid input trigger signal and remains in that state untilanother valid trigger signal is received.

Monostable Multivibrator

A switcing circuit with one stable output state. Also call one-shot. The one-shot . Produces a single output pulse when it receives a valid inout trigger signal.

Astable Multivibrator

A switching circuit that has no stable output state. The astable multivibrator is a rectangular-wave oscillator. Also referred to as a free-running multivibrator.

Filter

A circuit capable of passingor ampifying certain frequencies while attentuating othe frequencies. These can extract important frequencies from signals that also contain undesirable or irrelevant frequencies.

Pasive Filter

Uses passive components; Most responsive to a frequency range from 100Hz to 300MHz

Active Filter

Implements on integrated circuit. Capable of dealing wih very low frequencies.

Low-Pass Filter

Offers easy passage of low-frequency. It is used to remove noise (high-frequency signal) from a signal

High-Pass Filter

Offers easy passage to high frequency. Used in stereo system in adjusting treble.

Band-Pass Filter

Used to isolate voice frequencies

Band-Stop Filter

Used to remove voiec frequencies from music.