ASVAB Study Guide Electronics Information

ASVAB Study Guide Electronics Information Amperes Amperes (amps) are the number of electrons moving past a given point in one second Ohms Ohms are used to measure resistance and are used to describe the way electron flow is being limited V = Voltage I = Current R = Resistence V = IR Volts Volts are units which are used to measure how much work is being done when electrons are moving from one point to another point. Current Current is a describes electron flow/moving from one point to another point. Conductors Conductor is anything which works to assist electric current in its ability to flow Insulators An insulator is anything which works to prevent electric current from flowing Watts Watts are units which are used to measure how much energy is being consumed. Related to this are watt-hours, which measure the amount of energy used in an hour. The most common way to measure electricity is to measure in kilowatt hours, the amount of energy which is used in a single hour by a single kilowatt of electricity. Circuit Circuit is a series of components through which electric current flows. Impedance An impedance anything (including components) which changes the way the current flows. Resistance Resistance is a type of impedance. In resistance, electrical energy is converted into heat. Power Power is generally defined as the rate that work is being done or amount of energy being used per unit of time. Electrical power is the rate that electric energy is being moved by a circuit. Watt is used to describe power and is one joule per second. Direct Current DC is a one directional flow of current. Alternating Current AC is a flow of current that reverses its direction of flow on a periodic basis. Basic Electronic Units: Energy = Power = Charge = Voltage = Current = Frequency = Capacitance = Inductance = Resistance = Energy = joule (J) Power = watt (W) Charge = coulomb (C) Voltage = volt (V) Current = ampere (A) Frequency = hertz (Hz) Capacitance = farad (F) Inductance = henry (H) Resistance = ohm (Ω) Switch An electronic component which can be used to either divert current from one conductor to another conductor or to stop the flow of the current. Resistor A two-terminal electronic component that is used to add resistance to an electrical circuit. Inductor A two-terminal electronic component which resists any changes in the current which passes through it. Diode A component which is used to produce asymmetric conductance. It allows current to flow in one one direction. Fuse A fuse is a component which is rated for a specific current and is used to prevent the flow of electrical current from hitting a level above that rating Ground A ground is the most common return path for an an electrical current. This is the point from which voltages are measured. This also helps prevent unwanted transference of electricity Battery A battery is, usually, an electrochemical cell which is used to store energy in the form of chemicals and then, when is use, to change that chemical energy into electrical energy. Capacitor A capacitor is used to store energy through electrostatics. Transistor Transistor is used to amplify and modify electronic signals and current. Solder Solder is a fusible metal alloy with a low melting point (one lower than that of the pieces that is being used on) which is used to join together components. Flux Flux is a substance which is used to help increase both the melting and the flow of metal. It is used along with solder to help facilitate metal joining. Multimeter A multimeter is a digital electronic testing tool which can be used to measure a variety of things including voltage, resistance, and current. Voltmeter The analog version of a multimeter Oscilloscope An oscilloscope is a device which is used to display changes in the voltage over a period of time. Frequency Counter A frequency counter is used to measure frequency Ohmeter Measures resistance Ammeter used to measure current in a circuit Pulse Generator used to create rectangular pulses to test circuits Power Supply Power supplies are used to supply electrical energy to a load device Signal Generator A signal generator is a device which create electronic signals either in analog or digital form. Digital Pattern Generator Is used to make stimuli for digital electronics