GLOSSARY [Basic Radio Repair Vol. 1 (1963)]

Accelerating Anode: An anode placed at a high potential (2000 v) to accelerate the electron beam in a cathode ray tube.

A·C Voltmeter: A rectifier circuit combined with a d-c voltmeter to measure a-c voltage.

Alignment: Adjustment of the receiver's tuned circuits for maximum selectivity, sensitivity and output.

Amplifier: A circuit using tubes or transistors to increase the signal voltage, current or power.

Used at r-f, i-f, and audio frequencies.

Antenna: A device consisting of a predetermined length or shape of wire or rods, used to radiate and/or absorb r-f energy.

Attenuator: A voltage divider used to remove a portion of the signal with the least possible loss of signal frequencies.

Balance Control: Used to adjust and balance out bucking currents in an a-c rectifier circuit for a-c voltmeters.

Battery: A device used for converting chemical energy to electrical energy.

Blocking Capacitor: A capacitor used to permit the passage of the a-c components while blocking the d-c component of a varying d-c voltage.

Cathode Ray Oscilloscope: An instrument used to display a-c voltage waveforms.

Cathode Ray Tube: A specially constructed tube allowing control and display of applied a-c voltage waveforms.

Components: An inclusive term for all individual devices used to make up a receiver.

Contact Bias: A grid bias voltage developed by the stray electrons that strike the grid on their way to the plate.

Copper Oxide Rectifier: A series of tightly clamped, copper oxide coated discs separated by lead washer. It is used as a meter circuit rectifier.

Current Limiting Resistor: A resistor placed in the circuit to impede and limit current flow.

C•W Signal: An r-f signal of continuous frequency and continuous amplitude.

D'Arsonval Meter Movement: Most commonly used meter movement consisting of a coil balanced between the poles of a magnet.

Deflection: The back and forth, or up and down movement of the electron beam in a cathode ray tube.

Dynamic Mutual Conductance: The quotient of a small change in plate current divided by the small change in control grid voltage producing it, with all other electrode voltages held constant.

EM Speaker: Using a coil of wire to generate an electromagnetic field for a dynamic loudspeaker.

Floating Common: Where the B-minus common return line is isolated from the receiver chassis.

Fluorescence: The property of a phosphor in emitting light when struck by an electron beam.

Focusing: Controlling the electron beam in a cathode ray tube to converge at the faceplate for a sharp spot of light.

Grid-Dip Meter: Used to find the frequency of a resonant circuit.

Harmonic Frequencies: An integral multiple of a fundamental frequency. The second harmonic is twice that of the fundamental or first harmonic.

High-Fidelity: An audio circuit capable of handling, without loss or distortion, the full range of audio frequencies.

Loading: Using a low impedance meter circuit to measure small values of voltage in a high impedance circuit.

Modulation: The process of varying the amplitude (AM), the frequency (FM), or the phase (PM) of a carrier wave in accordance with a signal conveying intelligence.

Multimeter: A combination of multipliers and shunts using a single, basic meter movement to allow a wide range of metering.

Multiplier: A resistance used in series with a basic meter movement to extend its range in reading voltages.

Oscillator: A circuit used to convert dc to ac at a frequency determined by the circuit constants.

Peak Inverse Voltage: The maximum voltage applied between anode and cathode when the rectifier is not conducting.

PM Speaker: Using a permanent magnet to generate an electromagnetic field for a dynamic loudspeaker.

Power Supply: A source of voltage, both ac and dc, for application to the receiver circuits.

Probe: A small self-contained holder used as an extension lead from the meter to the circuit being probed. May contain isolating resistors, multiplier resistors, or detectors as determined by the use of the probe.

Push-pull: Two amplifier circuits connected in such a way that one operates on a positive alternation and the other operates on the negative alternation.

Retrace: The electron beam in cathode ray tube drawing a portion of the signal on the faceplate as it is being pulled back to start a new trace.

Sawtooth Voltage: A voltage shaped as a tooth in a saw, used for deflection in a cathode ray tube.

Shielding: Metallic covering used to prevent magnetic or electrostatic coupling between adjacent circuits.

Shunt: A resistance, or impedance, paralleling another component or circuit.

Signal Injection: Use of a signal generator to inject a substitute signal in a receiver.

Signal Tracing: Using a signal tracer to detect and amplify signals in tuned circuits up to the detector and as an audio amplifier to detect audio signals after the receiver detector.

Slug Tuning: Varying the value of inductance in tuning a resonant circuit.

Spark Plate: A specially constructed mica capacitor used at the input of the battery voltage to an automobile receiver. The construction aids in effective removal of high-frequency noise generated in the auto ignition system.

Synchronization: Sweeping the beam across the face of a cathode ray tube in step with the signal under observation.

Thyratron: A gas-filled tube employing a grid for control of the tube's ionization or "firing" point.

Time Constant: The time of rise or decay of voltage or current in an RC or RL circuit, as deter mined by- the values of RC or RL.

Volt-Ohm Milliammeter (VOM): A combination of multipliers and shunts using a single basic meter movement to allow a wide range of metering of voltage, resistance and current.

Vacuum Tube Voltmeter (VTVM): A vacuum tube operated multimeter providing increased sensitivity.

Variable Frequency Oscillator (VFO}: An oscillator circuit whose output frequency can be tuned over a specified range, usually employing a calibrated dial allowing resetting of the output frequency.

Vibrator: An electromechanical device used to switch the d-c voltage of a battery to an interrupted d-c voltage similar to a square wave for application to the primary of a power transformer.

Voice Coil: A low impedance coil connected to the speaker cone and inserted in an air gap in the speaker's magnetic field. Applying an audio signal to the voice coil causes it to move axially against the magnetic field to produce sound waves.

Whip Antenna: A short vertical antenna usually mounted on an automobile.

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INDEX TO VOL. I NOTE: A cumulative index covering both volumes in this series is included at the end of Volume II.