Duty cycle
Encyclopedia
In engineering
, the duty cycle of a machine or system is the time that it spends in an active state as a fraction of the total time under consideration.
The term is often used pertaining to electrical devices, e.g., switching power supplies. A 60% duty cycle means the power is on 60% of the time and off 40% of the time. The "on time" for a 60% duty cycle could be a fraction of a second – or for say, irrigation pumps, days – depending on how long the device's period is. Here one period is the length of time it takes for the device to go through a complete on/off cycle. The term "duty cycle" has no agreed meaning for aperiodic devices.
where
is the duration that the function is active
is the period of the function.
runs for one out of 100 seconds, or 1/100 of the time, and therefore its duty cycle is 1/100, or 1 percent.
divided by the pulse period. For example, a pulse train in which the pulse duration is 1 μs and the pulse period is 4 μs has a duty cycle of 25%. The pulse duration is normally calculated for positive pulses unless "negative duty cycle" is specified.
The duty cycle of a non-rectangular waveform, such as a sine or triangle wave, is defined as the fraction of the period the waveform spends above 0.
converter, the mean proportion of binary
"1" digits at the converter output
in which each "1" indicates a run of a specified number of consecutive bits of the same polarity in the digital
output signal.
(PWM).
, the maximum duty cycle is defined as the percentage of time in a 10 minute period that it can be operated continuously before overheating.
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, the duty cycle of a machine or system is the time that it spends in an active state as a fraction of the total time under consideration.
The term is often used pertaining to electrical devices, e.g., switching power supplies. A 60% duty cycle means the power is on 60% of the time and off 40% of the time. The "on time" for a 60% duty cycle could be a fraction of a second – or for say, irrigation pumps, days – depending on how long the device's period is. Here one period is the length of time it takes for the device to go through a complete on/off cycle. The term "duty cycle" has no agreed meaning for aperiodic devices.
Definition
In a periodic event, duty cycle is the ratio of the duration of the event to the total period.- duty cycle
where
is the duration that the function is active is the period of the function.Electrical machines
A motorMotor
Motor is a device that creates motion. It usually refers to an engine of some kind. It may also specifically refer to:*Electric motor, a machine that converts electricity into a mechanical motion...
runs for one out of 100 seconds, or 1/100 of the time, and therefore its duty cycle is 1/100, or 1 percent.
Electronics
In an ideal pulse train (one having rectangular pulses), the duty cycle is the pulse durationPulse duration
In signal processing and telecommunication, the term pulse duration has the following meanings:#In a pulse waveform, the interval between the time, during the first transition, that the pulse amplitude reaches a specified fraction of its final amplitude, and the time the pulse amplitude drops,...
divided by the pulse period. For example, a pulse train in which the pulse duration is 1 μs and the pulse period is 4 μs has a duty cycle of 25%. The pulse duration is normally calculated for positive pulses unless "negative duty cycle" is specified.
The duty cycle of a non-rectangular waveform, such as a sine or triangle wave, is defined as the fraction of the period the waveform spends above 0.
Digital signal processing
In a continuously variable slope delta (CVSD) modulationContinuously variable slope delta modulation
Continuously variable slope delta modulation is a voice coding method. It is a delta modulation with variable step size Continuously variable slope delta modulation (CVSD or CVSDM) is a voice coding method. It is a delta modulation with variable step size Continuously variable slope delta...
converter, the mean proportion of binary
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...
"1" digits at the converter output
Output
Output is the term denoting either an exit or changes which exit a system and which activate/modify a process. It is an abstract concept, used in the modeling, system design and system exploitation.-In control theory:...
in which each "1" indicates a run of a specified number of consecutive bits of the same polarity in the digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
output signal.
Electronic music
Music synthesizers vary the duty cycle of their audio-frequency oscillators to obtain a subtle effect on the tone colors. This technique is known as pulse-width modulationPulse-width modulation
Pulse-width modulation , or pulse-duration modulation , is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches....
(PWM).
Welding
In a welding power supplyWelding power supply
A welding power supply is a device that provides an electric current to perform welding. Welding usually requires high current and it can need above 12,000 amperes in spot welding. Low current can also be used; welding two razor blades together at 5 amps with gas tungsten arc welding is a good...
, the maximum duty cycle is defined as the percentage of time in a 10 minute period that it can be operated continuously before overheating.