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Amplifier Basics 1-5
Electronics
Question | Answer |
---|---|
What is Amplifier Coupling? | Allows the cascading (connecting in series) of amplifiers to transfer energy (signals) from one stage to another. |
Into which groups are amplifiers classified? | Function and Frequency Response. |
How do you get maximum power on amplifier coupling? | Match the impedances. |
Why is Transformer Coupling used? | It provides excellent impedance matching with increased gain. |
What does adding a parallel capacitor accomplish in Transformer Coupling? | Gives Selectivity. |
What is the least used method of Amplifier Coupling? | Impedance Coupling |
In RC Coupling, what is the coupling element? | The capacitor |
Describe the RC Time of Cc and Rb in relation to the input signal. | The RC time of Cc and Rb is LONG to the input signal. |
What type of coupling provides the best frequency response? | Direct Coupling |
What is the process of coupling a portion of the output signal back to the input of an amplifier for control called? | Feedback |
What are the CLASSES of feedback? | Positive and Negative |
What is another word for positive feedback? | Regenerative |
What is another word for negative feedback? | Degenerative |
What are the TYPES of feed back? | Voltage, Current, and Combination. |
What is an Open Loop? | A system without feedback. |
What is Closed Loop? | A system with feedback. |
What is the equation for Gain Without Feedback? | Av = Vout / Vin |
What is the equation for Gain With Feedback? | Af = Av / (1- Av * B) |
What is B in the Gain With Feedback (Af) equation? | B = feedback facotor |
What is Shunt Voltage Feedback | Feedback applied IN PARALLEL with input signal. |
What are the types of audio amplifiers? | Single-Ended, Push-Pull, and Complementary Symmetry Push-Pull. |
Which Class should single-ended audio amplifiers operate in? | Class A |
Which type of audio amplifier is identified with two transistors? | Push-Pull |
Which Class should a Push-Pull audio amplifier operate in? | Class AB |
What are Phase Splitters and Phase Inverters? | Circuits that provide two signals equal in amplitude and opposite in polarity. And are used to drive Push-Pull audio amplifiers. |
What type of amplifier is used when maximum power and gain are required? | Transformer |
What type of amplifier is used when good frequency response is required. | Single-Stage/Split-Load Phase Inverter |
What type of amplifier is used when high power output and fidelity are required. | Complimentary-Symmetry Push-Pull |
Why is negative feedback used? | To improve frequency response. |
What is an Oscillator? | A circuit that generates an AC signal at a frequency determined by the value of its components and at a constant peak amplitude. |
What are the basic components of an oscillator? | Frequency Determining Network (FDN), Amplifier, Feedback. |
What are the types of oscillators? | Armstrong, Hartley, Colpitts, RC Phase Shift. |
The ability of crystals to generate an electric field is called? | Pizo Electric Effect |
What are the two types of Hartley Oscillators? | Series Fed and Shunt Fed. |
How is an Armstrong Oscillator identified? | Tickler Coil |
How is an Hartley Oscillator identified? | Split inductors |
How is an Colpitts Oscillator identified? | Split capacitors |
How is an RC Phase Shift Oscillator identified? | Resistors and Capacitors. |
The amount of Phase Shift in an RC Phase Shift Oscillator is determined by: | Ratio of resistance to Xc. |
What is the voltage at which a sudden increase in a reverse current across a PN junction occurs? | Breakdown Voltage |
What is the Zener Effect? | Breakdown below 5 volts. |
What is the Avalanch Effect? | Breakdown above 5 volts. |
What does a Zener Diode do? | Acts as a Voltage Regulator. |
What is the formula for Capacitance in a Varactor Diode? | C = kA / d |
What does JFET stand for? | Junction Field Effect Transistor |
What is a JFET transisitor's normal state? | On |
How do you stop current through a JFET transistor? | Apply voltage to the Gate. |
What does the JFET Transistor use to control current flow? | An Electrostatic Field. |
What type of signal do Rectifiers output? | Pulsating DC |
What type of input signal do rectifiers receive? | AC |
A signal being converted from AC to DC moves through which devices? | Transformer, Rectifier, Filter, Regulator, Load. |
In a Half-Wave Rectifier what is the formula for Average Voltage? | Eavg = (Epeak * .636) / 2 |
Why are bleeder resistors used? | SAFETY of equipment and personnel, and to PREVENT ELECTRICAL SHOCK. |
What is REGULATION? | When you keep the voltage constant. |