Push pull meaning

Push-pull Definition & Meaning - Merriam-Webster


: relating to or being an arrangement of two electronic circuit elements (such as transistors) such that an alternating input causes them to send current through a load alternately

a push-pull circuit

push-pull noun

Word History

First Known Use

1920, in the meaning defined above

Time Traveler

The first known use of push-pull was in 1920

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push plate



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Cite this Entry



“Push-pull.Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/push-pull. Accessed 28 Dec. 2022.

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Push-pull Definition & Meaning | Dictionary.

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  • British

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[ poosh-pool ]

/ ˈpʊʃˈpʊl /

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This shows grade level based on the word's complexity.


Radio. a two-tube symmetrical arrangement in which the grid excitation voltages are opposite in phase.


of or relating to electronic devices having components with balanced signals opposite in phase.



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Origin of push-pull

First recorded in 1925–30

Words nearby push-pull

push paper, pushpin, push plate, push poll, push polling, push-pull, pushrod, push shot, push someone's buttons, push-start, push the envelope

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

Words related to push-pull

convulse, jolt, shake, shock, sway, swing, agitate, billow, careen, concuss, falter, heave, jiggle, jog, jounce, lurch, move, oscillate, pitch, quake

How to use push-pull in a sentence

  • It is a spy series at its core, but you guys never really pull from the headlines.

    ‘Archer’ Creator Adam Reed Spills Season 6 Secrets, From Surreal Plotlines to Life Post-ISIS|Marlow Stern|January 8, 2015|DAILY BEAST

  • Instead, straighten your civic backbone and push back in clear conscience.

    Why We Stand With Charlie Hebdo—And You Should Too|John Avlon|January 8, 2015|DAILY BEAST

  • In Afghanistan, there was a push to take back the southern province Helmand.

    Pentagon Doesn’t Know How Many People It’s Killed in the ISIS War|Nancy A. Youssef|January 7, 2015|DAILY BEAST

  • Doubling down on Schedule I is, at best, a deranged way to push Americans away from “medical,” and toward recreational, use.

    Obama’s Pot Policy Is Refer Madness|James Poulos|January 5, 2015|DAILY BEAST

  • After some animated debate at the conference, Lelaie declared, with some frustration, “If you push on the stick, you will fly.”

    Flight 8501 Poses Question: Are Modern Jets Too Automated to Fly?|Clive Irving|January 4, 2015|DAILY BEAST

  • The sense of bearing on to the voice, or endeavoring to push the tone by any pressure whatever, should be absolutely avoided.

    Expressive Voice Culture|Jessie Eldridge Southwick

  • Strange to say, the silken cord yielded to the first pull, as if nothing had been wrong with it at all!

    The Giant of the North|R.M. Ballantyne

  • Thereupon the governor attacked him alone, and giving a violent push on the door, opened it.

    The Philippine Islands, 1493-1898, Volume XX, 1621-1624|Various

  • Never grasp a Fern plant from above and try to pull it away, as this will be almost sure to result in damage.

    How to Know the Ferns|S. Leonard Bastin

  • One Turkish Company, about a hundred strong, was making an ugly push within rifle shot of our ship.

    Gallipoli Diary, Volume I|Ian Hamilton

British Dictionary definitions for push-pull


noun (modifier)

using two similar electronic devices, such as matched valves, made to operate 180° out of phase with each other. The outputs are combined to produce a signal that replicates the input waveforma push-pull amplifier

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

How 2-stroke and 4-stroke engines work

Product catalog Outboard motors and boats How 2-stroke and 4-stroke engines work

When choosing power equipment, special attention must be paid to the type of engine. There are two types of internal combustion engines: 2-stroke and 4-stroke.

The principle of operation of an internal combustion engine is based on the use of such properties of gases as expansion when heated, which is carried out due to the forced ignition of a combustible mixture injected into the air space of the cylinder. nine0005

You can often hear that a 4-stroke engine is better, but to understand why, you need to take a closer look at the principles of operation of each.

The main parts of an internal combustion engine, regardless of its type, are the crank and gas distribution mechanisms, as well as systems responsible for cooling, power, ignition and lubrication of parts.

The transfer of the useful work of the expanding gas is carried out through a crank mechanism, and the gas distribution mechanism is responsible for the timely injection of the fuel mixture into the cylinder. nine0005

Four-stroke engines - Honda's choice

Four-stroke engines are economical, while their operation is accompanied by a lower noise level, and the exhaust does not contain a combustible mixture and is much more environmentally friendly than a two-stroke engine. That is why Honda uses only four-stroke engines in the manufacture of power equipment. Honda has been introducing its four-stroke engines to the power market for many years and has achieved the highest results, while their quality and reliability have never been questioned. But still, let's look at the principle of operation of 2 and 4 stroke engines. nine0005

Working principle of two-stroke engine

The duty cycle of a 2-stroke engine consists of two stages: compression and power stroke.

Compression . The main piston positions are top dead center (TDC) and bottom dead center (BDC). Moving from BDC to TDC, the piston alternately closes first the purge and then the exhaust port, after which the gas in the cylinder begins to compress. At the same time, a fresh combustible mixture enters the crank chamber through the inlet window, which will be used in subsequent compression. nine0005

Working stroke . After the combustible mixture is compressed as much as possible, it is ignited by an electric spark generated by a candle. At the same time, the temperature of the gas mixture rises sharply and the volume of the gas grows rapidly, exerting a pressure at which the piston begins to move towards the BDC. As the piston descends, it opens the exhaust port, while the combustion products of the combustible mixture are released into the atmosphere. Further movement of the piston compresses the fresh combustible mixture and opens the purge hole through which the combustible mixture enters the combustion chamber. nine0005

The main disadvantage of a two-stroke engine is the high fuel consumption, and some of the fuel does not have time to benefit. This is due to the presence of a moment at which the purge and outlet openings are simultaneously open, which leads to a partial release of the combustible mixture into the atmosphere. There is also a constant oil consumption, since 2-stroke engines run on a mixture of gasoline and oil. Another inconvenience is the need to constantly prepare the fuel mixture. The main advantages of a two-stroke engine remain its smaller size and weight compared to a 4-stroke counterpart, but the size of power equipment allows you to use 4-stroke engines on them and experience much less hassle during operation. So the lot of 2-stroke engines is left to various modeling, in particular, aircraft modeling, where even an extra 100g matters. nine0005

How the four-stroke engine works

The operation of a four-stroke engine is significantly different from that of a two-stroke engine. The working cycle of a four-stroke engine consists of four stages: intake, compression, power stroke and exhaust, which is made possible by the use of a valve system.

During the intake stage , the piston moves down, the intake valve opens, and a combustible mixture enters the cylinder cavity, which, when mixed with the rest of the used mixture, forms the working mixture. nine0005

When is compressed, the piston moves from BDC to TDC, both valves are closed. The higher the piston rises, the higher the pressure and temperature of the working mixture.

Power stroke four-stroke engine is a forced movement of the piston from TDC to BDC due to the action of a rapidly expanding working mixture, ignited by a spark from a candle. As soon as the piston reaches BDC, the exhaust valve opens.

During the exhaust phase , the products of combustion displaced by the piston moving from BDC to TDC are released to the atmosphere through the exhaust valve. nine0005

Due to the use of a valve system, four-stroke internal combustion engines are more economical and environmentally friendly - after all, the emission of unused fuel mixture is eliminated. In operation, they are much quieter than 2-stroke counterparts, and much easier to operate, because they work on a regular AI-92, which you fill your car with. There is no need for constant preparation of a mixture of oil and gasoline, because the oil in these engines is poured separately into the oil sump, which significantly reduces its consumption. That is why Honda only produces 4-stroke engines and has achieved tremendous success in their production. nine0005

What is the difference between a two-stroke engine and a four-stroke engine, the principle of operation of a two-stroke engine

An internal combustion engine operates according to a long-studied principle. It is worth considering the operation of a piston engine in more detail, since rotary and other unusual devices that convert combustion energy into kinetic energy are less common. What is the main difference between a 2-stroke engine and a 4-stroke engine? The most important difference lies in the mode of ignition of the combustible mixture, which can be easily understood by the reproduction of sounds. A two-stroke motor produces a shrill sound in most cases, as well as a rather loud sound, while a four-stroke engine produces a calmer and more measured sound. nine0005

  • How a 2-stroke engine works
    • What does stroke mean?
    • Operation of a four-stroke engine
    • How the push-pull device works
    • The difference between a two-stroke engine and a four-stroke engine
    • What type of motor should I buy?
    • How much does it cost to repair equipment and replace parts?
    • Which motor to choose
    • Two-stroke engine Features:
  1. Most often, the difference is also mainly in the purpose of the device and its overall fuel efficiency. In a two-stroke type engine, the ignition process is reproduced with each revolution of the crankshaft, it is for this reason that in terms of power they are several times superior to four-stroke ones, in which there is a special mixture that goes mainly through revolutions.
  2. Four-stroke engines are much heavier and use the most energy. In most cases, they are used on cars and special equipment, while on other equipment such as scooters, lawn mowers, and light varieties of boats, in most cases, you can see more compact two-stroke varieties of devices. nine0064
  3. But a gasoline generator, for example, can be easily found in both two-stroke and four-stroke varieties. The engine in a scooter can also contain absolutely any engine. The principle of operation of such equipment mainly includes the same processes, the difference will be only in the method and efficiency of the overall energy conversion.

What does beat mean?

The process of fuel processing in both models of engines can be carried out using the sequential execution of all four types of processes, which are otherwise called cycles. The speed at which the main work of the engine is performed passes through three cycles - this is exactly what the main difference between a two-stroke engine and a four-stroke one is. nine0005

The first stroke is injection . At this time, the piston begins to move like a cylinder, and the intake valve begins to open to let the air-fuel mixture into itself and deliver it to the combustion chamber itself. After that, the combustion process will take place. At this time, the exhaust valve closes back, and the piston continues to move up the cylinder, compressing all the gases that are inside. The stroke of the working stroke occurs when the entire mixture is ignited. nine0005

At this time, the spark from the candle begins to replenish all the gases compressed in itself, which provokes an explosion, the energy of which pushes the piston down to its initial position. The last stroke will be considered exhaust: the piston will reach the top of the cylinder, and the exhaust valve will open again, allowing all exhaust gases to exit the common combustion chamber so that the process can be carried out again. The reciprocating motions in the piston rotate the crankshaft , while the torque is transmitted to the working parts in the equipment. This is how the process of converting the energy of fuel combustion into translational motion can take place. nine0005

Operation of a four-stroke engine

In a conventional four-stroke engine, ignition of the mixture starts every second revolution of the shaft. The process of rotating the shaft can result in more complex shaped mechanisms that will help the user achieve successive strokes.

Both the intake and exhaust valves can be opened by means of the camshaft which repeatedly presses the rocker arms. The process of returning the valve to the closed initial position is carried out under the influence of a spring. In order not to lose compression, it is worth making sure that the valve begins to fit as tightly as possible to the cylinder head. nine0005

How a two-stroke device works

Now it's worth considering in more detail the process of a two-stroke engine, as well as distinguishing its features from a four-stroke one. In a two-stroke engine, all four actions occur in one revolution of the shaft, during the piston stroke from top dead center to bottom, and then up again. The release of excess gases (i.e. purge) and fuel injection are integrated into one cycle, ultimately this process ignites the entire mixture, and the energy received produces a push of the piston down. This arrangement eliminates the particular need for valves in the device itself. nine0005

In place of the valves, several combustion chamber openings can be found at once . At that moment, when the piston is moved to its lowest point by means of the combustion movement, the exhaust valve will open, allowing all the exhaust gases to be eliminated, by this action the chamber will become completely empty again. During the downward movement, a vacuum is formed in the cylinder, with the help of which a certain mixture of air, as well as additional air, is drawn in through the exhaust valve located in the lower region. nine0005

During the upward movement of the piston, it begins to block all channels and is able to compress the gases inside the cylinder. At this time, the spark plug is fired, and after that the whole process described above occurs in a new way. It is important to note that in engines of this format, the process of ignition of the mixture can occur during each subsequent revolution. Which helps to extract more power from them, at least for a certain period of time.

Difference between 2-stroke and 4-stroke engine

Two-stroke engines will be best used in applications that need quick and sharp bursts of all energy, rather than a steady process of work over a long period of time. For example, a jet ski accelerates much faster than a simple four-stroke truck. But at the same time, is needed to make short trips , while the truck itself is able to travel a distance equal to hundreds of kilometers, until it needs to rest. nine0005

The short duration of the two-stroke mechanism will be compensated by its low weight to power ratio: these types of engines in most cases weigh much less, it is for this reason that they can start faster and reach the highest indicator of their efficiency, and can also reach the maximum operating temperature. To carry out their movement to another point, a much smaller value of energy is also expended. nine0005

Which type of motor should I buy?

In most cases, four-stroke engines can only run in one position. This may be due to the complexity of the moving mechanisms, as well as the designs of the oil pan.

This type of sump, which provides further lubrication of the engine, is most often found only in four-stroke devices and has the highest importance for the workflow. A two-stroke engine most often does not have any additional pallet, it is for this reason that they can be can be used in almost any position of without the possibility of splashing oil or interrupting the lubrication of the equipment. For types of equipment such as chainsaws, circular saws, and other personal tools, this flexibility is considered quite important.

Fuel efficiency and environmental impact. In most cases, it becomes clear that compact, as well as fast engines in devices, pollute the environment much faster and consume a large amount of fuel. At the bottom of the piston movement, when the combustion chamber is completely filled with a combustible mixture, a certain amount of fuel is completely lost, falling into an empty channel. nine0005

This can be easily seen when looking at the outboard motor. You can see multi-colored oil stains around it. It is for this reason that engines of this type are considered not very efficient and pollute the surrounding air. And although four-stroke models have a lot of weight and slow performance, but at the same time they burn fuel fully .

How much does it cost to repair equipment and replace parts?

Smaller devices are generally considered to be the cheapest, both in terms of initial purchase and further maintenance. But at the same time, they are calculated for a longer operating time. Although there are some out-of-bounds, but most often they are not designed for long-term operation for more than two hours and are designed for a very short period of use.

Lack of a separate lubrication system can also lead to this. That even in the highest quality motor of this type, wear will occur very quickly, and then it will become unusable due to damage to the moving part.

Partly due to the lack of lubrication in gasoline, which is needed to fill a two-stroke scooter engine, for example, it is worth adding some specialized oil. This can lead to additional costs of time and money, as well as can cause equipment to fail (if you ever forget to add new oil). A four-stroke type motor most often requires minimal care and maintenance from the consumer.

Which motor to choose

Four-stroke engine main features:

  1. One stroke is made for every two revolutions of the crankshaft.
  2. For its operation, the consumer has to use heavy flywheels to compensate for the vibration that can develop during engine operation due to the uneven distribution of torque, since the process of ignition of the combustible mixture will occur only at every second revolution. nine0064
  3. Large engine mass.
  4. The structure of the entire engine will be the most complex due to the complexity of the valve mechanism.
  5. The price of the device is high.
  6. Low mechanical efficiency due to strong friction between several parts.
  7. Higher performance by complete removal of exhaust gases and injection process of the freshest solution.
  8. Lower operating amplitude. nine0064
  9. Completion of water cooling.
  10. Less energy consumption and a complete combustion process.
  11. Occupies a significant space in the work area.
  12. Sophisticated lubrication system.
  13. Low noise level.
  14. The process of distributing gas using a valve mechanism.
  15. High thermal efficiency.
  16. Low oil consumption.
  17. The smallest process of wear of moving and interacting parts and mechanisms
  18. Can be installed in buses, trucks and other vehicles.