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Basic Circuit Function

  

A circuit is the closed loop through which electricity can flow. A closed circuit allows an uninterrupted flow of electricity from the source of power, through the conductor or wire, to the load, and then back again to the ground or source of power. An open circuit will not conduct electricity because either air, or some other insulator has stopped or broken the flow of current in the loop.

Maintained/Momentary Switches

Carling offers a wide range of circuit configurations with both maintained and momentary switch functions. A maintained switch maintains the mode or position to which it is actuated. For example, if switched to the "ON" position, the switch will remain in the "ON" position until it is physically switched to another position.

A momentary switch is a "spring return" switch which automatically returns to its original or at rest position. A simple example of a momentary switch would be a doorbell, which automatically returns back to its resting "OFF" position when no longer actuated.

Carling Technologies' catalogs denote momentary circuits using parenthesis. For example, the doorbell circuit would be represented as (ON)-NONE-OFF, where (ON) is the momentary position.

Normally Open/Normally Closed

Momentary switches can be described as normally open or normally closed, which refers to the switch's original or at rest position. A normally open or N.O. momentary switch has one or more circuits that are open when the switch actuator is at its normal or rest position. An "open" circuit is an incomplete circuit, with "open space" between contacts. Therefore a normally open circuit can also be referred to as "normally OFF".

A normally closed or N.C. momentary switch has one or more circuits that are closed when the switch actuator is at its normal or rest position. A closed circuit is a completed circuit. Therefore a normally closed circuit can also be referred to as "normally ON".

Throw

The throw of a switch is the number of circuit paths that can be controlled by any one pole. Usually the number of "ON" positions that a switch has is the same as the number of throws. A single throw switch (ST) opens or closes a circuit at only one of the extreme positions of its actuator, the most common example being an ON-NONE-OFF switch. A double throw switch (DT) switch opens or closes a circuit at both extreme positions of its actuator, a common example being an ON-NONE-ON switch.

ON-NONE-OFF

The ON-NONE-OFF or ON-OFF circuit is a maintained, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to place the switch to the ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position, where all switching circuits would be open.

OFF-NONE-ON

The OFF-NONE-ON or OFF-ON circuit is a maintained, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to place the switch to the OFF position, where all switching circuits would be open. You would press the bottom of the rocker or move a toggle downward to set the switch to the ON position.

(ON)-NONE-OFF

The (ON)-NONE-OFF or (ON)-OFF circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the momentary ON position. Because this is a normally open (N.O.) circuit, when you release the actuator it will automatically return to its normal at rest OFF position, where all switching circuits would be open.

ON-NONE-(OFF)

The ON-NONE-(OFF) or ON-(OFF) circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.

If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary OFF position, where all switching circuits would be open. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest, ON position.

OFF-NONE-(ON)

The OFF-NONE-(ON) or OFF-(ON) circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.

If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. Because this is a normally open (N.O.) circuit, when you release the actuator it will automatically return to its normal at rest OFF position, where all switching circuits would be open.

(OFF)-NONE-ON

The (OFF)-NONE-ON or (OFF)-ON circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the momentary OFF position, where all switching circuits would be open. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest, ON position.

ON-NONE-ON

The ON-NONE-ON or ON-ON circuit is a maintained, double throw, two-position switch circuit. In general, for basic unlighted single pole switches, ON positions close at the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 2 & 3; 4 & 5 and 5 & 6.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to set the switch to the first ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the second ON position. This switch circuit does not have an OFF position, where all switching circuits would be open.

ON-NONE-(ON)

The ON-NONE-(ON) or ON-(ON) circuit is a momentary, double throw, two-position switch circuit. In general, for basic unlighted single pole switches, the maintained ON position closes the circuit at switch terminals 2 & 3, and the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the maintained ON circuit is closed at terminals 2 & 3, 5 & 6; and the momentary ON circuit is closed at terminals 1 & 2, 4 & 5.

If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest maintained ON position. This switch circuit does not have an OFF position where all switching circuits would be open.

ON-OFF-ON

The ON-OFF-ON circuit is a maintained, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, ON positions close the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2, and 2 & 3; 4 & 5 and 5 & 6.

If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to set the switch to the first ON position. You would move the rocker or toggle actuator to the center position to set the switch to OFF, where all switching circuits would be opened. You would press the bottom of the rocker or move a toggle downward to set the switch to the second ON position.

ON-OFF-(ON)

The ON-OFF-(ON) circuit is a momentary, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, the maintained ON position closes the circuit at switch terminals 2 & 3, and the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the maintained ON circuit is closed at terminals 2 & 3,5 & 6; and the momentary ON circuit is closed at terminals 1 & 2, 4 & 5.

If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. When the actuator is released, it will return to the center OFF, at rest position. You would press the bottom of the rocker or move a toggle downward to set the switch to the maintained ON position. From this position, you would manually move the rocker or toggle actuator to the center position to set the switch to OFF, where all switching circuits would be open.

(ON)-OFF-(ON)

The (ON)-OFF-(ON) circuit is a momentary, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON positions close at the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 2 & 3; 4 & 5 and 5 & 6.

If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the first momentary ON position. You would press the bottom of the rocker or move a toggle downward to move the switch to the second momentary ON position. This is a normally open (N.O.) circuit, therefore whenever you release the actuator it will automatically return to its normal at rest center OFF position, where all switching circuits would be opened.

ON-ON-ON

The ON-ON-ON or PROGRESSIVE circuit is typically a maintained, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuit 2 is ON at terminal 2 & 3; in the mid position Circuit 1 & 2 are ON from terminals 4 & 5 and 2 & 3 respectively; and in the third position Circuit 1 is ON from terminals 4 & 5.

If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the Circuit 2 ON position. You would move the rocker or toggle actuator to the center position to move the switch to the Circuit 1 & 2 ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the Circuit 1 ON position.

The ON-ON-ON circuit can also be a maintained, single pole, triple throw, three-position switch. In this case, a jumper is usually provided between poles at terminals 2 & 4 to link the common terminal 5 with the three output terminals 1, 3 & 6.

If the switch were mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the first ON position at terminals 5 & 6. You would move the rocker or toggle actuator to the center position to move the switch to the second ON position at terminals 5 & 3. And you would press the bottom of the rocker or move a toggle downward to set the switch to the third ON position at terminals 5 & 1.

ON-ON-OFF

The ON-ON-OFF is another type of PROGRESSIVE circuit that is a maintained, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuits 1 & 2 are ON at terminals 5 & 6 and 2 & 3; in the mid position Circuit 1 is ON at terminals 2 & 3, and in the third position both circuits are OFF.

If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the Circuit 1 & 2 ON position. You would move the rocker or toggle actuator to the center position to move the switch to the Circuit 1 ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position.

A typical application example for this type of circuit would be HEADLIGHTS - RUNNING LIGHTS - OFF.

The ON-ON-OFF circuit is also offered as a maintained, single pole switch in a double pole base. In this configuration Circuit 2 is ON in the first position at terminals 2 & 3. In the mid-position Circuit 1 is ON at terminals 1 & 2, and in the third position both circuits are OFF.

(ON)-ON-OFF

The (ON)-ON-OFF is a third type of PROGRESSIVE circuit that is a momentary, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuits 1 & 2 are in the momentary ON position at terminals 5 & 6 and 2 & 3; in the mid position Circuit 1 is maintained ON at terminals 2 & 3, and in the third position both circuits are OFF.

If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the momentary Circuit 1 & 2 ON position. When the actuator is released, it will return to the center Circuit 1 maintained ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position, where both circuits would be open.

A typical application example would be OFF - RUN ENGINE - (START ENGINE).

OTHER CIRCUITS

Carling Technologies offers a number of specialized circuits including reversing two position and reversing three position configurations. Specialty hazard circuits and other specialty circuits for transportation industries are also available. Carling also offers four and eight position rotary switches. If you have specialized circuit needs, please contact your Carling Technologies Sales Representative for assistance.