The alternating current power supply The symbol in the illustration symbolizes an alternating current power source. An alternating current (AC) is one that switches direction periodically with respect to voltage, for example, as opposed to a direct current (DC) which has no switching direction. Alternating current was once the only type available but it is now used mainly for remote control functions. It is still used in many situations where direct current operation would be inconvenient or inefficient.
The term "power supply" refers to any device that provides electrical energy to some other device. In this case, the power supply is the electric wall outlet that feeds electricity into the circuit. Other devices on the circuit include light bulbs and appliances such as refrigerators, air conditioners, heat pumps, and washing machines. They all require electricity to work.
Electrical power is the ability of a system to do work. Electrical power is measured in watts. If you multiply the voltage across a conductor by its current through that conductor, you get power. For example, if you have 1 amp flowing through a wire with 120 volts across it, then that's 12 watts of power being delivered to your appliance. Electricity is transmitted to homes and businesses over long distances on copper wires called lines.
Voltage (alternating current) The voltage sign is represented by a capital V with a wavy line on top. When you wish to measure the voltage of an object, you must turn the dial to this symbol. If no scale is provided, the value will be indicated in volts by a small V next to the symbol.
For example, if you see the word "120" next to the voltage symbol, then the meter should be set to read 120 volts. If there are other markings on the meter, such as degrees Celsius or ohms, they will also appear at that location on the meter.
The voltage symbol was first introduced in 1922 by the American Radio Relay League (ARRL), and it's usage became standard after the introduction of multimeters in 1956. Before that time, voltmeters were either mechanical or electronic, and they used various symbols for different ranges of voltage. For example, before the adoption of the modern voltage symbol, other common symbols included:
• A black dot within a circle for zero voltage
• Two crossed wires for open circuit/ground
• A single red wire for short circuit/power
• A green triangle for voltage measurement
The correct answer is C. The resistor symbol (attached). In an electric circuit, the symbol would best depict an electric fan. A resistor slows down the flow of current through it; a fuse prevents any current from flowing through it.
Resistors are used to control current flow in circuits. Current flows through each resistor in a circuit until it reaches a point where all the resistors get hot enough to break down. At this point, the current can no longer flow through them and they no longer affect the circuit.
The two main types of resistors are polymers and ceramics. Polymer resistors are usually brown or black and come in a variety of sizes from small fractions of a ohm up to many thousands of ohms. They tend to be expensive but offer very precise resistance values without changing shape or coloration with use. Polymer resistors work on the principle of electrons being blocked by pins stuck into the surface of the resistor. As more and more pins are pushed into the surface of the resistor, more and more electrons are blocked resulting in a higher resistance. This means that polymer resistors can be made to any degree of precision.
Ceramic resistors are just what they sound like: thin discs of ceramic material with wires running through them.
The AC voltage sign resembles a "A" with "a road" on top of it. It has a "A" above it with three dashes and a straight line. This is how the value being measured is read. This is a set of semicircle marks on an analog multitester. Voltage, current, and resistance may all be seen in the above example. The term "analog" means that these measurements are not digital (0 or 1). They are always a number between 0 and whatever limit is set by the meter.
The multimeter can measure many things besides voltage. It can measure current, resistors, capacitors, and inductors. For more information about what each mark on the multimeter means, check the manual or do some research on your own.
In conclusion, the voltage symbol looks like a "A" with "a road" on top of it. This is how you identify what type of measurement you are taking on a multimeter.