Intro to Electronics - CH's 12-17
About this set
Created by:
terry_2005 on February 19, 2012
Subjects:
1-1111-2853-7, AC, AC Measurements, Resistive AC Circuits, Capacitive AC Circuits, Inductive AC Circuits, Resonance Circuits, Transformers
Description:
Introduction to Electronics, 6th Ed, Eric Gates
AC
AC Measurements
Resistive AC Circuits
Capacitive AC Circuits
Inductive AC Circuits
Resonance Circuits
Order by
101 terms
Terms | Definitions |
|---|---|
 Two types of electricity | Direct current (DC) Alternating current (AC) |
| AC generator | Converts mechanical energy into electrical energy. |
| Electromagnetic Induction | The process of inducing a voltage in a conductor by passing it through a magnetic field. |
| Maximum voltage is induced when... | the conductor is moved perpendicular to the lines of flux. |
| When the conductor is moved PARALLEL to the lines of flux... | NO voltage is induced. |
| Cycle | One revolution of an AC generator. (Also, two complete alternations of voltage with NO reference to time.) |
| Alternations | the two halves of an AC cycle. (one positive & one negative) |
| Hertz (Hz) | One cycle per second. |
| Major parts of an AC generator | Armature Field Slip Rings Brushes |
| AC generator output | Sinusoidal wave form (Sine wave) |
| Sine wave values (pair of numbers) | Degree of rotation- armature's position in the field. Amplitude-value in relation to maximum or minimum. |
| Peak value | Absolute value (no negative numbers) of the point of greatest magnitude. (The peak of the curve-positive or negative) |
| Peak to Peak | Max positive to Max negative. (Add the absolute values) |
| Effective value | The amount that produces the same degree of heat in a given resistance as an equal amount of DC. |
| RMS value | Root Mean Square - same as effective value. Is calculated mathematically. |
| What value does a multimeter measure? | RMS value. (effective value) |
| Formula for RMS value | E rms = Ep X .707 |
| Period | The time required to complete one cycle. Measured in seconds. |
| Frequency | The number of cycles that occurs in a specific period of time. (Usually cycles per second) |
| The unit of frequency is | the hertz |
| The period of a sine wave is | inversely proportional to its frequency. (higher freq-lower period) |
| Frequency-period formula | f= 1/t f=frequency t=period |
| Nonsinusoidal waveforms | Other than sine wave. Square, triangular, saw tooth |
| Pulse width | (Square wave) The duration that the voltage is at the max or min amplitude. Pulse width is one half of the period-hence square. |
| Triangular wave | Linear rise in value. Positive and negative ramps of equal slope. |
| Saw tooth wave | (Special triangular wave) Long, linear positive ramp with rapid negative ramp |
| Fundamental Frequency | The repetition rate of the waveform |
| Harmonics | Higher frequency sine waves that are exact multiples of the fundamental frequency. |
| Square wave harmonics | Fundamental frequency and all ODD harmonics |
| Triangular wave harmonics | Fundamental frequency and all ODD harmonics AND all are 180 degrees out of phase. |
| Sawtooth wave harmonics | ODD and EVEN harmonics. Even are 180 degrees out of phase with odd. |
| Moving Coil Meter | d'Arsonval meter movement |
| Moving coil meters are designed to measure.. | DC current |
| How is AC current measured with a moving coil meter? | The AC current must first be converted to DC. |
| Rectification | The process of converting AC current to DC. Accomplished with diodes. |
| Rectifier output | pulsating DC (sine wave is flipped to all positive alternations) |
| Clamp on ammeter | A split core transformer. It is clamped around the conductor and uses the voltage induced by the conductors magnetic field |
| Oscilloscope provides the following data: | Frequency Duration Phase relationship (of 2 or more waveforms) Shape of a waveform Amplitude |
| Parts of an oscilloscope: | Cathode Ray Tube Sweep generator Horizontal deflection amp Vertical deflection amp Power supply |
| Iron vane meter movement does not require | conversion to DC |
| In phase | Phase relationship such that current and voltage pass through peaks and zeros at the same time. |
| In Phase relationship |  |
| Purely resistive circuits are | IN PHASE. Voltage and current pass through max and zero at the same point. |
| Current is always ____ in a resistive circuit | In phase with voltage. |
| Power in a resistive AC circuit. Power is always positive. |  |
| Most widely used measurement value for AC | Effective (RMS) value |
| Does current flow across a capacitor? | NO! The capacitor charging and discharging results in movement of electrons from one plate to the other. This resembles current flow. |
| Capacitive AC circuit - I >C>E |  |
| Capacitive reactance formula |  |
| Capacitive Reactance | The opposition that a capacitor offers to the applied AC voltage. |
| ICE | Current (I) leads Voltage(E) in a capacitive circuit (C) I>C>E (Remember ELI the ICE man.) |
| Capacitive Circuit Operation | Voltage starts from zero. Capacitor is empty. Current becomes max. Capacitor charges. Current drops as voltage becomes max and capacitor nears full charge. At max voltage capacitor is fully charged & current drops to zero. Voltage drops towards negative. Capacitor opposes and negative current flows as capacitor discharges. |
| Capacitive Reactance in Parallel | 1/XCT = 1/XC1 + 1/XC2 + 1/XC3 ... + 1/XCn |
| Capacitive Reactance in Series | XCT = XC1 + XC2 + XC3 ... + XCn |
| RC Low Pass Filter |  |
| RC Low Pass Operation | Allows low frequencies to pass while attenuating high frequency. At low frequency, capacitive reactance is HIGH so voltage drop is across capacitor. |
| RC High Pass Filter |  |
| RC High Pass Operation | Allows high frequency to pass while attenuating low. At high frequency, capacitive reactance is LOW so voltage drop is across the resistor. |
| Low Pass Frequency Response |  |
| High Pass Frequency Response |  |
| Decoupling Network | Allows a DC signal to pass while blocking the AC signal. |
| What type of circuit can be used as a decoupling network? | RC low-pass filter. |
| Coupling Network | Passes the AC signal while blocking the DC |
| What type of circuit can be used as a coupling network? | An RC high-pass filter |
| Filter | A circuit that discriminates against certain frequencies. |
| RC circuit uses | Filtering (low/high pass) Coupling(and decoupling) Phase shifting |
| RC phase shift networks are used only where | small amounts (less than 60 degrees) are desired. |
| RC leading output phase-shift network |  |
| Inductive Reactance | The opposition to current flow by an inductor in an AC circuit. |
| Counter Electromotive Force (CEMF) | Voltage induced in an inductor coil which opposes the applied voltage. It is out of phase by 180 degrees. |
| Factors effecting CEMF | The greater the rate of change of the magnetic field (faster the magnetic field expands or collapses) the greater the CEMF. |
| ELI | Voltage (E) leads Current (I) in an inductive (L) circuit E>L>I |
| Inductive Reactance Formula |  |
| Impedance Formula |  |
| Decoupling Network - Memory Trick | D-coupling = d C pass |
| Coupling Network - Memory Trick | C-oupling = a C pass |
| RC Low pass filter - Memory Trick |  Capacitor low = frequency low (Capacitor low in schematic. Low frequency passes) |
| RC High pass filter - Memory Trick |  Capacitor high=frequency high (Capacitor high in schematic. High frequency passes) |
| Leading Output Phase-Shift Network Memory Trick | Look for C. (C slows voltage) C in back - input slow-output leads. Output voltage leads input voltage. |
| Lagging Output Phase-Shift Network Memory Trick |  Look for C. (C slows voltage) C in front-output slow-input leads. Output voltage lags input voltage. |
| Impedance | The combined effect of resistive and reactive components. It is the vector sum. |
| Why is the capacitive voltage vector (Ec) drawn downward? | It lags current by 90 degrees. This is why it points down (-90 degrees). |
| Why are current vectors used to analyze a PARALLEL circuit? | Because the VOLTAGE is the SAME across all components. All are EQUAL and IN PHASE with current, so that vector is the horizontal (X) axis. |
| Why are voltage vectors used to analyze a SERIES circuit? | Because the CURRENT is the SAME across all components. All are EQUAL and IN PHASE with voltage, so that vector is the horizontal (X) axis. |
| Power Factor | The ratio of true power (in watts) to apparent power (in volt-amperes) in a REACTIVE circuit. |
| Power factor of RESISTIVE circuit | True power EQUALS apparent power so power factor is 1. (1/1=1) |
| The value of capacitive reactance _______ as frequency increases |  decreases (inversely proportional) High freq=low Xc |
| What is the formula for cutoff frequency in an RC circuit? |  |
| Counter electromotive force (cemf) | Voltage induced in an inductor coil by the expansion and collapse of the magnetic field resulting from an applied voltage. |
| CEMF characteristics | Always opposes applied voltage. Greater inductance=greater cemf Always 180 degrees out of phase with applied voltage. |
| Induced voltage is always _____ than applied voltage | LESS THAN |
| In a purely inductive circuit current ___ voltage. | LAGS - remember ELI the ICE man. E(voltage) L(inductive circuit) I(current) Current lags by 90 degrees. |
| The opposition to current flow by an inductor in an AC circuit is | inductive reactance (Xl) measured in ohms |
| Inductive reactance formula |  |
| Inductive reactances in series | When inductors are connected in series, the total inductive reactance is equal to the sum of the individual inductive reactance values |
| Formula for inductive reactance in series |  |
| Formula for inductive reactances in parallel |  |
| RL Low pass filter |  |
| RL High pass filter |  |
| RL cutoff frequency formula |  |
| RL Circuit Vector Formula |  |
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