Worksheets

Fig. 1

12

Name Resistor

A resistor symbol stands for a component that opposes current. The zigzag (US style) and the plain rectangle (IEC style) are two drawings of the same component.

Fig. 2

12

Name Variable resistor

A diagonal arrow through the resistor body marks a variable resistor.

Fig. 3

1W2

Name Potentiometer

A potentiometer has three terminals: the two ends of the resistive track and a wiper, drawn as an arrow touching the body.

Fig. 4

12

Name Rheostat

A rheostat is a variable resistor used with two terminals: one end of the track and the wiper.

Fig. 5

12

Name Thermistor

A thermistor's resistance changes with temperature. NTC resistance falls as temperature rises; PTC resistance rises. A generic thermistor symbol without a type label does not distinguish the two.

Fig. 6

12

Name Light-dependent resistor

Two arrows arriving at a resistor body mark a light-dependent resistor (photoresistor).

Fig. 1

12

Name Resistor

A resistor symbol stands for a component that opposes current. The zigzag (US style) and the plain rectangle (IEC style) are two drawings of the same component.

Fig. 2

12

Name Variable resistor

A diagonal arrow through the resistor body marks a variable resistor.

Fig. 3

1W2

Name Potentiometer

A potentiometer has three terminals: the two ends of the resistive track and a wiper, drawn as an arrow touching the body.

Fig. 4

12

Name Rheostat

A rheostat is a variable resistor used with two terminals: one end of the track and the wiper.

Fig. 5

12

Name Thermistor

A thermistor's resistance changes with temperature. NTC resistance falls as temperature rises; PTC resistance rises. A generic thermistor symbol without a type label does not distinguish the two.

Fig. 6

12

Name Light-dependent resistor

Two arrows arriving at a resistor body mark a light-dependent resistor (photoresistor).

Fig. 1

12

Name Capacitor

A capacitor symbol stands for two conductors separated by an insulator; the two parallel plates are a picture of that.

Fig. 2

+−

Name Polarised capacitor

In the polarised capacitor drawings here, + marks the positive terminal. The US form has a curved negative plate; the IEC form has a hollow positive plate. The marked polarity must be respected.

Fig. 3

12

Name Variable capacitor

In the variable-capacitor convention used here, a diagonal arrow through the plates indicates adjustable capacitance.

Fig. 4

12

Name Capacitor

A capacitor symbol stands for two conductors separated by an insulator; the two parallel plates are a picture of that.

Fig. 5

+−

Name Polarised capacitor

In the polarised capacitor drawings here, + marks the positive terminal. The US form has a curved negative plate; the IEC form has a hollow positive plate. The marked polarity must be respected.

Fig. 6

12

Name Variable capacitor

In the variable-capacitor convention used here, a diagonal arrow through the plates indicates adjustable capacitance.

Fig. 1

12

Name Capacitor

A capacitor symbol stands for two conductors separated by an insulator; the two parallel plates are a picture of that.

Fig. 2

+−

Name Polarised capacitor

In the polarised capacitor drawings here, + marks the positive terminal. The US form has a curved negative plate; the IEC form has a hollow positive plate. The marked polarity must be respected.

Fig. 3

12

Name Variable capacitor

In the variable-capacitor convention used here, a diagonal arrow through the plates indicates adjustable capacitance.

Fig. 4

12

Name Capacitor

A capacitor symbol stands for two conductors separated by an insulator; the two parallel plates are a picture of that.

Fig. 5

+−

Name Polarised capacitor

In the polarised capacitor drawings here, + marks the positive terminal. The US form has a curved negative plate; the IEC form has a hollow positive plate. The marked polarity must be respected.

Fig. 6

12

Name Variable capacitor

In the variable-capacitor convention used here, a diagonal arrow through the plates indicates adjustable capacitance.

Fig. 1

AK

Name Diode

A diode conducts much more readily in its forward direction than in its reverse direction. Real devices also have leakage and reverse breakdown, which this page's simplified models omit.

Fig. 2

AK

Name Light-emitting diode

Two arrows leaving the diode body mark a light-emitting diode.

Fig. 3

AK

Name Zener diode

Bent ends on the cathode bar mark a Zener diode, a diode meant to be used in reverse breakdown.

Fig. 4

AK

Name Schottky diode

Hooked ends on the cathode bar mark a Schottky diode.

Fig. 5

AK

Name Photodiode

Two arrows arriving at the diode body mark a photodiode.

Fig. 1

AK

Name Diode

A diode conducts much more readily in its forward direction than in its reverse direction. Real devices also have leakage and reverse breakdown, which this page's simplified models omit.

Fig. 2

AK

Name Light-emitting diode

Two arrows leaving the diode body mark a light-emitting diode.

Fig. 3

AK

Name Zener diode

Bent ends on the cathode bar mark a Zener diode, a diode meant to be used in reverse breakdown.

Fig. 4

AK

Name Schottky diode

Hooked ends on the cathode bar mark a Schottky diode.

Fig. 5

AK

Name Photodiode

Two arrows arriving at the diode body mark a photodiode.

Fig. 1

12

Name Inductor

An inductor stores energy in a magnetic field and opposes changes in current; its symbol represents the coil.

Fig. 2

12

Name Iron-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 3

12

Name Ferrite-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 4

12

Name Inductor

An inductor stores energy in a magnetic field and opposes changes in current; its symbol represents the coil.

Fig. 5

12

Name Iron-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 6

12

Name Ferrite-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 1

12

Name Inductor

An inductor stores energy in a magnetic field and opposes changes in current; its symbol represents the coil.

Fig. 2

12

Name Iron-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 3

12

Name Ferrite-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 4

12

Name Inductor

An inductor stores energy in a magnetic field and opposes changes in current; its symbol represents the coil.

Fig. 5

12

Name Iron-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 6

12

Name Ferrite-core inductor

In the coil convention used here, solid parallel core lines indicate iron and dashed core lines ferrite. The unmarked coil is used for air core. These drawings do not identify every material detail.

Fig. 1

P1P2S1S2

Name Transformer

The separate-winding transformer shown here transfers energy magnetically between windings without an internal conducting connection between them. This description excludes an autotransformer, whose windings share a conducting connection.

Fig. 2

P1P2S1S2CT

Name Centre-tapped transformer

A centre tap is an electrical connection at the midpoint of a winding, shown as an extra lead from that winding.

Fig. 3

P1P2S1S2

Name Air-core transformer

In the transformer drawings here, parallel lines between windings indicate a magnetic core, drawn as iron-core examples. The air-core example omits these lines; another drawing's legend may use a plain coil more generally.

Fig. 4

P1P2S1S2

Name Transformer

The separate-winding transformer shown here transfers energy magnetically between windings without an internal conducting connection between them. This description excludes an autotransformer, whose windings share a conducting connection.

Fig. 5

P1P2S1S2CT

Name Centre-tapped transformer

A centre tap is an electrical connection at the midpoint of a winding, shown as an extra lead from that winding.

Fig. 6

P1P2S1S2

Name Air-core transformer

In the transformer drawings here, parallel lines between windings indicate a magnetic core, drawn as iron-core examples. The air-core example omits these lines; another drawing's legend may use a plain coil more generally.

Fig. 1

P1P2S1S2

Name Transformer

The separate-winding transformer shown here transfers energy magnetically between windings without an internal conducting connection between them. This description excludes an autotransformer, whose windings share a conducting connection.

Fig. 2

P1P2S1S2CT

Name Centre-tapped transformer

A centre tap is an electrical connection at the midpoint of a winding, shown as an extra lead from that winding.

Fig. 3

P1P2S1S2

Name Air-core transformer

In the transformer drawings here, parallel lines between windings indicate a magnetic core, drawn as iron-core examples. The air-core example omits these lines; another drawing's legend may use a plain coil more generally.

Fig. 4

P1P2S1S2

Name Transformer

The separate-winding transformer shown here transfers energy magnetically between windings without an internal conducting connection between them. This description excludes an autotransformer, whose windings share a conducting connection.

Fig. 5

P1P2S1S2CT

Name Centre-tapped transformer

A centre tap is an electrical connection at the midpoint of a winding, shown as an extra lead from that winding.

Fig. 6

P1P2S1S2

Name Air-core transformer

In the transformer drawings here, parallel lines between windings indicate a magnetic core, drawn as iron-core examples. The air-core example omits these lines; another drawing's legend may use a plain coil more generally.

Fig. 1

12

Name Switch (SPST)

A switch symbol stands for a contact that either completes or breaks a path.

Fig. 2

12

Name Push button, normally open

The momentary push buttons shown here change contact state while pressed and return to their drawn, unactuated state when released.

Fig. 3

12

Name Push button, normally closed

Switch contacts are drawn in their normal status: the position they rest in with no force applied. A normally-open (NO) contact is drawn open and a normally-closed (NC) contact closed; for a momentary push button, normal means not pressed.

Fig. 4

COM12

Name Switch (SPDT)

Poles count the separate circuits a switch controls; throws count the contact destinations available to each pole. An off position is not an additional throw.

Fig. 5

COM11A1BCOM22A2B

Name Switch (DPDT)

Poles count the separate circuits a switch controls; throws count the contact destinations available to each pole. An off position is not an additional throw.

Fig. 1

12

Name Switch (SPST)

A switch symbol stands for a contact that either completes or breaks a path.

Fig. 2

12

Name Push button, normally open

The momentary push buttons shown here change contact state while pressed and return to their drawn, unactuated state when released.

Fig. 3

12

Name Push button, normally closed

Switch contacts are drawn in their normal status: the position they rest in with no force applied. A normally-open (NO) contact is drawn open and a normally-closed (NC) contact closed; for a momentary push button, normal means not pressed.

Fig. 4

COM12

Name Switch (SPDT)

Poles count the separate circuits a switch controls; throws count the contact destinations available to each pole. An off position is not an additional throw.

Fig. 5

COM11A1BCOM22A2B

Name Switch (DPDT)

Poles count the separate circuits a switch controls; throws count the contact destinations available to each pole. An off position is not an additional throw.

Fig. 1

1

Name Earth ground

In the convention used here, three horizontal lines of decreasing length identify a connection to earth. Check a drawing's legend: the same shape is sometimes used more generally for circuit ground.

Fig. 2

1

Name Chassis ground

The chassis symbol (hatched) marks a connection to the equipment's metal frame or enclosure.

Fig. 3

1

Name Signal reference (common)

The signal-reference symbol marks the chosen zero-volt reference for circuit voltages. It need not be connected to earth or chassis.

Fig. 4

1

Name Earth ground

In the convention used here, three horizontal lines of decreasing length identify a connection to earth. Check a drawing's legend: the same shape is sometimes used more generally for circuit ground.

Fig. 5

1

Name Chassis ground

The chassis symbol (hatched) marks a connection to the equipment's metal frame or enclosure.

Fig. 6

1

Name Signal reference (common)

The signal-reference symbol marks the chosen zero-volt reference for circuit voltages. It need not be connected to earth or chassis.

Fig. 1

1

Name Earth ground

In the convention used here, three horizontal lines of decreasing length identify a connection to earth. Check a drawing's legend: the same shape is sometimes used more generally for circuit ground.

Fig. 2

1

Name Chassis ground

The chassis symbol (hatched) marks a connection to the equipment's metal frame or enclosure.

Fig. 3

1

Name Signal reference (common)

The signal-reference symbol marks the chosen zero-volt reference for circuit voltages. It need not be connected to earth or chassis.

Fig. 4

1

Name Earth ground

In the convention used here, three horizontal lines of decreasing length identify a connection to earth. Check a drawing's legend: the same shape is sometimes used more generally for circuit ground.

Fig. 5

1

Name Chassis ground

The chassis symbol (hatched) marks a connection to the equipment's metal frame or enclosure.

Fig. 6

1

Name Signal reference (common)

The signal-reference symbol marks the chosen zero-volt reference for circuit voltages. It need not be connected to earth or chassis.

Fig. 1

+−

Name Cell

In a cell symbol the long thin line is the positive terminal and the short thick line is the negative terminal.

Fig. 2

+−

Name Battery

A battery is drawn as several cells in a row; the terminals follow the same long-positive rule.

Fig. 3

+−

Name DC voltage source

The generic DC voltage-source drawing used in both views is a circle with + and − signs. An ideal voltage source fixes the voltage difference between those terminals.

Fig. 4

12

Name AC source

The sinusoidal AC voltage-source drawing used here is a circle with a sine wave inside.

Fig. 5

12

Name Current source

The generic current-source drawing used in both views is a circle with an arrow giving conventional current direction. An ideal current source fixes that current; the arrow does not give voltage polarity.

Fig. 1

+−

Name Cell

In a cell symbol the long thin line is the positive terminal and the short thick line is the negative terminal.

Fig. 2

+−

Name Battery

A battery is drawn as several cells in a row; the terminals follow the same long-positive rule.

Fig. 3

+−

Name DC voltage source

The generic DC voltage-source drawing used in both views is a circle with + and − signs. An ideal voltage source fixes the voltage difference between those terminals.

Fig. 4

12

Name AC source

The sinusoidal AC voltage-source drawing used here is a circle with a sine wave inside.

Fig. 5

12

Name Current source

The generic current-source drawing used in both views is a circle with an arrow giving conventional current direction. An ideal current source fixes that current; the arrow does not give voltage polarity.