Connections, Wires, Passive Components, etc...

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This section describes schematic symbols for connections, wires, passive components and other related things. CLICK HERE IF YOU CAME FROM A WEB SEARCH

Non Polarized Fixed Capacitor: A capacitor is a device that stores electrons. The basic capacitor is made up of two conductors seperated by an insulator, or dielectric. Depending on how the capacitor is built, the dielectric can be made of paper, plastic, mica, ceramic, glass, a vacume or any other such non conductive material. Capacitor electron storing ability (it's capacitance) is measured in Farads. One Farad is actually a huge number of electrons (6,280,000,000,000,000,000 electrons to be exact), so we usually rate capacitors in microfarads (uF) and picofarads (pF). One uF is equal to 0.000,001F and one pF is equal to 0.000,000,000,001F. A non polar capacitor is a type of capacitor that can be connected any way in a circuit. In other words, there is no positive or negative. Common types of non polar capacitors are ceramic, mica and some electrolytics.
Polarized Fixed Capacitor: A capacitor is a device that stores electrons. The basic capacitor is made up of two conductors seperated by an insulator, or dielectric. Depending on how the capacitor is built, the dielectric can be made of paper, plastic, mica, ceramic, glass, a vacume or any other such non conductive material. Capacitor electron storing ability (it's capacitance) is measured in Farads. One Farad is actually a huge number of electrons (6,280,000,000,000,000,000 electrons to be exact), so we usually rate capacitors in microfarads (uF) and picofarads (pF). One uF is equal to 0.000,001F and one pF is equal to 0.000,000,000,001F. A polar capacitor is a type of capacitor that can only be connected one way in a circuit. In other words, they have a positive and negative lead. The positive lead is shown on the schematic with a little "+" symbol. Most polar capacitors are electrolytics, meaning that the dielectric is made up of a thin layer of oxide formed on an aluminium or tantalum foil. This foil is also the conductor.
Variable Capcitor: A capacitor is a device that stores electrons. The basic capacitor is made up of two conductors seperated by an insulator, or dielectric. Depending on how the capacitor is built, the dielectric can be made of paper, plastic, mica, ceramic, glass, a vacume or any other such non conductive material. Capacitor electron storing ability (it's capacitance) is measured in Farads. One Farad is actually a huge number of electrons (6,280,000,000,000,000,000 electrons to be exact), so we usually rate capacitors in microfarads (uF) and picofarads (pF). One uF is equal to 0.000,001F and one pF is equal to 0.000,000,000,001F. A variable capacitor is a capacitor whose capacitance can be varied. They are usually made up of one or more moving plates and one or more non moving plates seperated by the dielectric. By moving the plates, we can vary the capacitance. These types of capacitor are usually used in radio tuners, oscillators, etc.
Resistor: Resistors are one of the most common electronic componens. A resistor is a device that limits, or resists current. Reisistor can be made from many different materials, but the most common is carbon composition. The carbon composition resistor is basically a small, thin section of carbon composition (carbon with a few binding agents, etc...) with a lead at each end. Each lead is connected to parts of the circuit. The current limiting ability, or resistance can be varied by changing the ratio of carbon to binding agent. Resistance is measured in ohms, represented by the Greek symbol Omega (W [if you see a "W" here instead of the Omega, then you don't have the necessary fonts installed]). You will often see the resistance of resistors written with K (kilohms) after the number value. This means that there are that many thousands of ohms. For example, 1K is 1000 ohm, 2K is 2000 ohm, 3.3K is 3300 ohm, etc. You may also see the suffix M (megohms). This simply means million. Resistors are also rated by their power handling capability. This is the amount of heat the resistor can take before it is destroyed. The power capability is measured in W (watts), with 1/4 W, 1/2W, 1W, 5W and 10W being common. Note that you can have tiny resistors down to fractions of 1/4W, or huge resistors measuring in the thousands of watts.
Variable Resistor (Potentiometer): Resistors are one of the most common electronic componens. A resistor is a device that limits, or resists current. The current limiting ability, or resistance is measured in ohms, represented by the Greek symbol Omega (W [if you see a "W" here instead of the Omega, then you don't have the necessary fonts installed]). Variable resistors (also called potentiometers or just "pots") are resistors that have a variable resistance. You adjust the resistance by turning a shaft. This shaft moves a wiper accross the actual resistor element. By changing the amounts of resistor between the wiper connection and the connection (s) to the resistor element, you can change the resistance. You will often see the resistance of resistors written with K (kilohms) after the number value. This means that there are that many thousands of ohms. For example, 1K is 1000 ohm, 2K is 2000 ohm, 3.3K is 3300 ohm, etc. You may also see the suffix M (megohms). This simply means million. Resistors are also rated by their power handling capability. This is the amount of heat the resistor can take before it is destroyed. The power capability is measured in W (watts). Common wattages for variable resistors are 1/8W, 1/4W, 1/2W and 1W. Anything of a higher wattage is referred to as a rehostat.
Transformer: Transformers are a type of inductor made up of two or more coils usually wound on some type of form. This form (or core) is usually made up of iron, due to it's magnetic properties. When current flows though one winding, a magnetic field is created. When that current is cut off, that field collapses. Any time there is a variation in the magnetic field, electricity is induced (or transferred to) in the other coil(s). For this reason, transformers work on an AC voltage or pulsing DC voltage only. Depending on the ratio of the wires between the primary winding and the secondary winding, the voltage can either be stepped up, down, or remain the same. More wire on the secondary side causes the voltage to be stepped up and current stepped down (a step up transformer). Less wire on the secondary causes the voltage to be stepped down and current up (a step down transformer). When there are equal amounts of wire on each side of the transformer, it becomes an isolation transformer. These isolate one section of a circuit from another, since there is no direct electrical connection. The transformer pictured in the above image is an isolation transformer. Note that some schematics have dashed lines or no lines at all between the coils. Dashed lines represent a ferrite core. No lines represent an air core.
Wires Not Connected: There is no connection between these wires on the schematic. They are crossing each other.
Wires Connected: These wires are connected on the schematic.
Connection (Usually to V+): This arrow usually refers to a connection to V+, or the supply voltage of the circuit. Note that different people may also use the symbol for the output of the circuit or as a connection to something else. Usually what it is connected to is shown on the schematic.
Connection (Usually to V-): This arrow pointing down usually refers to a connection to V-, or the negative supply voltage of the circuit. Note that different people may also use the symbol for the output of the circuit or as a connection to something else. Usually what it is connected to is shown on the schematic.
Circuit Ground: The ground of the circuit. If the circuit is battery powered, this usually refers to the negative terminal of the battery. If the circuit is line powered, then this either refers to the ground on the mains or the negative connection on the line powered supply. Note that if the circuit is powered by a dual voltage (+, - and ground), the ground is the point at 0 volts. In this case, ground is also the green connection on the power supply. Also note that some people use circuit ground and earth ground to mean the same thing. It is more confusing that way.
Switch: A switch is used to turn an electrical flow on and off. The switch symbols on schematics can vary widely, but most look something like this. Pictured here is a simple SPST (or Single Pole Single Throw) swtich. This means the the switch contains one set of contacts and can only be switched one way (on or off). Other types of switches include SPDT (Single Pole Double Throw-A switch with one contact that can be toggled both ways), DPST (Double Pole Single Throw-A switch with two contacts that can only be on or off) and DPDT (Double Pole Double Throw-A switch with two contacts that can be toggled both ways).
Normally Closed Push Button: A switch is used to turn an electrical flow on and off. A push button is a switch in the form of a button. In this case, the button is normally closed. That is, when you push the button the current is cut off. When you release the button, the current is on. Some push buttons are of the push-on-push-off type, meaning that one push turns it on, then another turns it off.
Normally Open Push Button: A switch is used to turn an electrical flow on and off. A push button is a switch in the form of a button. In this case, the button is normally open. That is, when you push the button the current is flows. When you release the button, the current flow stops. Some push buttons are of the push-on-push-off type, meaning that one push turns it on, then another turns it off.
Connection (Usually Output): This symbol represents a circuit output. This output may be used for signal, power, etc. Whatever connects to the output is usually shown in the schematic. Note that some people also use this to represent an input.
Connection (Input): This symbol represents a circuit input. This input may be used for signal, power, etc. Whatever connects to the input is usually shown in the schematic. Note that this is not interchangable with the output. This is simply an input, as represented by the arrow facing in.
Power Plug, Connection To Mains: Since this is the standard plug we all see on power cords, this symbol stands for a line cord, or connection to mains (120VAC, 220VAC, etc...). If this were a three prong grounded type plug, there would be a third prong on the symbol.
Thermistor: Resistors are one of the most common electronic componens. A resistor is a device that limits, or resists current. Reisistor can be made from many different materials, but the most common is carbon composition. The carbon composition resistor is basically a small, thin section of carbon composition (carbon with a few binding agents, etc...) with a lead at each end. Each lead is connected to parts of the circuit. The current limiting ability, or resistance can be varied by changing the ratio of carbon to binding agent. Thermistors differ from regular resistors in that their resistance is determinded by temperature. They can be either positive coefficient or negative coefficient. In positive coefficient units, the resistance goes up when the termperature goes up. In negative coefficient units, the resistance goes down as the temperature goes up. Resistance is measured in ohms, represented by the Greek symbol Omega (W [if you see a "W" here instead of the Omega, then you don't have the necessary fonts installed]). You will often see the resistance of resistors written with K (kilohms) after a number value. That means that there are that many thousands of ohms. For example, 1K is 1000 ohm, 2K is 2000 ohm, 3.3K is 3300 ohm, etc. You may also see the suffix M (megohms). This simply means million.
Earth Ground: This means quite literally a ground connection to the Earth. This is often used in radio receivers. Most Earth ground connections are made to a metal cold water pipe or long metal rod driven into the Earth. Note that some people use the symbols for Earth ground and circuit ground interchangably.
Inductor: Inductors are basically a coil of wire that may or may not be wrapped around a core. Inductors resist a rapid change in the current flow through them because of the effects of the magnetic field they create as that current flows. Because of ths propery, they are often used as filtering in power supplies. Inductors are also used in radios and other tuned circuits to form what is called a tank circuit. A tank circuit is basically a type of oscillator. Some inductors have a variable value. This is accomplished by using a screw to move the core in and out of the coil. These types of inductors are usually used in radios. Inductor value is measured in Henrys (H) or more commonly microhenrys (uH).
Antenna: An antenna is a structure (made of wire, metal rods, etc.) for receiving or transmitting radio signals. There are many different antenna conffiguartions, but most schematics use this one to represent a standard antenna. Other types of antennas include dipole, loop and telescopic.
Shielded Cable: Shielded cable is cable with a metal mesh or foil around it to shield against interference from radio, computers, etc. The shield is usually grounded. Shielded cables may have more than one conductor. In schematics, this is represented by more than one line inside the circle.
Fuse: A fuse is a thin piece of wire designed to melt at a specific current. For example, a 10A fuse would work up to 10A. After the current exceeds 10A, the excess heat will cause the wire to melt, which breaks the connection. In this way, fuses are used to protect against excess currents flowing though a circuit.
Fuseable Resistor: Fusable resistors are resistors that, when the current exceeds a certain amount, act like fuses. That is, they "blow out" and cut off the current. A resistor is a device that limits, or resists current. The current limiting ability, or resistance is measured in ohms, represented by the Greek symbol Omega (W [if you see a "W" here instead of the Omega, then you don't have the necessary fonts installed]). A fuse is a thin piece of wire designed to melt at a specific current. For example, a 10A fuse would work up to 10A. After the current exceeds 10A, the excess heat will cause the wire to melt, which breaks the connection. In this way, fuses are used to protect against excess currents flowing though a circuit.
Shielding: Shielding is some sort of metal container the contains electromagnetic interference. Shielding is usually applied to high gain circuits and circuits that either give out or can receive interference. Most shields consist of a metal box or cover that goes over the circuit and either connectes to circuit ground or earth ground.
Phono Jack: A phono jack is a small jack that has two conductors; ground and signal. The signal is the hole in the center jack (represented on the schematic by the circle inside the other circle). The ground is the metal surrounding the signal jack. The name "phono jack" came from the fact that these jacks were origionally used to connect record players to early radios. Some other common names for these jacks are "RCA Jack" and "Audio Jack". Note that this symbol is also used to represent a coaxial jack.
Phono Plug: The phono plug is the plug that connects to a phono jack. There are two connectors on the phono plug; signal and ground. Signal is the round rod poking out from the center. Ground is the metal circle that surrounds it. The name "phono pkug" came from the fact that these plugs were origionally used to connect record players to early radios. Some other common names for these pugs are "RCA Plug" and "Audio Audio". Note that this symbol is also used to represent a coaxial plug.
Two Conductor Plug: Two conductor plugs are generally used for a power connection or as a connection to a mono sound source. The two conductors are called the sleeve and the tip. The sleeve is usually used as ground and is represented on the schematic by the small line sticking out under the tip. The tip is usually used for signal and is represented on the schematic by the line sticking out with the circle on the end.
Three Conductor Plug: Three conductor plugs are generally used for a stereo audio connection or sometimes to transmit serial computer data. The three conductors are called the sleeve, the ring and the tip. The sleeve is usually used as ground and is represented on the schematic by the small line sticking out under the ring. Thr ring is the slightly longer line located under the tip. The tip is usually used for signal and is represented on the schematic by the line sticking out with the circle on the end.
Two Conductor Jack: Two conductor jacks are designed to accept a two conductor plug. On the schematic, the rectangle makes contact with the sleeve on the plug and the "bent line" makes contact with the tip on the plug. Two conductor jacks will also accept three conductor plugs, although only two contacts will be used. These jacks will also sometimes be seen with a built in switch, which looks like an arrow pointing at the tip connection. Two conductor plugs are generally used for a power connection or as a connection to a mono sound source. The two conductors are called the sleeve and the tip. The sleeve is usually used as ground and is represented on the schematic by the small line sticking out under the tip. The tip is usually used for signal and is represented on the schematic by the line sticking out with the circle on the end.
Three Conductor Jack: Three conductor jacks are designed to accept a three conductor plug. On the schematic, the rectangle makes contact with the sleeve on the plug, the first "bent line" makes contact with the ring on the plug and the second bent line makes contact with the tip on the plug. Three conductor jacks will also accept two conductor plugs, although only two contacts will be used. These jacks will also sometimes be seen with a built in switch, which looks like an arrow pointing at the tip connection. Three conductor plugs are generally used for a stereo audio connection or sometimes to transmit serial computer data. The three conductors are called the sleeve, the ring and the tip. The sleeve is usually used as ground and is represented on the schematic by the small line sticking out under the ring. Thr ring is the slightly longer line located under the tip. The tip is usually used for signal and is represented on the schematic by the line sticking out with the circle on the end.
Rotary Switch: A switch is used to turn an electrical flow on and off. The switch symbols on schematics can vary widely, but most look something like this. Pictured here is a simple SPST (or Single Pole Single Throw) swtich. This means the the switch contains one set of contacts and can only be switched one way (on or off). Other types of switches include SPDT (Single Pole Double Throw-A switch with one contact that can be toggled both ways), DPST (Double Pole Single Throw-A switch with two contacts that can only be on or off) and DPDT (Double Pole Double Throw-A switch with two contacts that can be toggled both ways). Rotary switches are switches with many contacts. The contacts are selected by turning a shaft. The shaft moves a wiper accross the various contacts. Rotary switches are often seen with 4,6,8 and 10 contacts, although switches with many more contacts are available. Rotary switches may be single pole or double pole. The amount of contacts on a rotary switch is representd by the number in front of the type of switch. For example, a SP4T rotary switch has 4 contacts and a single pole and 4 contacts. A 6 contact double pole switch would look like DP6T.

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