G-6

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SUBELEMENT G6 – CIRCUIT COMPONENTS

[2 Exam Questions – 2 Groups]

G6A – Resistors; Capacitors; Inductors; Rectifiers; solid state diodes and transistors; vacuum tubes; batteries

 

10.5 volts is the minimum allowable discharge voltage for maximum life of a standard 12 volt lead acid battery. High discharge current is an advantage of the low internal resistance of nickel-cadmium batteries. It is never acceptable to recharge a carbon-zinc primary cell

0.3 volts is the approximate junction threshold voltage of a germanium diode. 0.7 volts is the approximate junction threshold voltage of a conventional silicon diode. Lower capacitance is an advantage of using a Schottky diode in an RF switching circuit rather than a standard silicon diode

Its saturation and cutoff regions are the stable operating points for a bipolar transistor used as a switch in a logic circuit. Some large power transistors are insulated from ground to avoid shorting the collector or draining voltage to ground. In a MOSFET the gate is separated from the channel with a thin insulating layer. A field effect transistor is most like a vacuum tube in its general operating characteristics.

To reduce grid-to-plate capacitance is the primary purpose of a screen grid in a vacuum tube. In a triode vacuum tube the control grid is used to regulate the flow of electrons between cathode and plate.

The polarity of applied voltages is important for polarized capacitors because incorrect polarity can cause the capacitor to short-circuit, reverse voltages can destroy the dielectric layer of an electrolytic capacitor and the capacitor could overheat and explode. Comparatively low cost is an advantage of ceramic capacitors as compared to other types of capacitors. High capacitance for a given volume is an advantage of an electrolytic capacitor.

If the temperature of a resistor is increased the resistor will change depending on the resistor’s temperature coefficient. A reason not to use wire-wound resistors in an RF circuit is the resistor’s inductance could make circuit performance unpredictable. The winding axes of two solenoid inductors are oriented at right angles to each other to minimize their mutual inductance. An advantage of using a ferrite core toroidal inductor is large values of inductance may be obtained, magnetic properties of the core may be optimized for a specific range of frequencies and most of the magnetic field is contained in the core.

 G6B – Analog and digital integrated circuits (ICs); microprocessors; memory; I/O devices; microwave ICs (MMICs); display devices

The term ROM means Read Only Memory. Memory is characterized as non-volatile when the stored information is maintained even if power is removed.

Linear voltage regulator is an analog integrated circuit. Integrated circuit operational amplifier is an analog device. Low power consumption is an advantage of CMOS integrated circuits compared to TTL integrated circuits. A computer on a single integrated circuit is a microprocessor

The term MMIC is a Monolithic Microwave Integrated Circuit

 

An LED is forward biased when emitting light. Lower power consumption, faster response time and longer life are the advantages of an LED indicator compared to an incandescent indicator.

A characteristic of a liquid crystal display is it requires ambient or back lighting.

In an Amateur Radio station a computer and transceiver might be connected using a USB interface. DE-9 connector would be a good choice for a serial data port.

PL-259 is commonly used for RF connections at frequencies up to 150 MHz. A type N connector is a moisture-resistant RF connector useful to 10 GHz. A small threaded connector suitable for signals up to several GHz is a type SMA connector. RCA Phono is commonly used for audio signals in Amateur Radio stations. A family of multiple circuit connectors suitable for audio and control signals is the general description of a DIN type connector. Reduced chance of incorrect mating is the main reason to use keyed connectors instead of non-keyed types.

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