pushpull

Push-pull is a design principle in which two complementary devices or actions alternately drive a load. One component handles the positive half of a waveform or motion, while the other handles the negative half. The approach can improve efficiency, reduce distortion, or provide balanced control. The term is often written as push-pull or pushpull.

In electronics, push-pull often refers to a class of amplifiers that use two active devices (transistors or tubes) to source and sink current. Each device conducts during its half-cycle, which lowers even-order distortion and increases efficiency. Practical implementations include transformer-coupled push-pull, and complementary-symmetry designs such as class B and class AB amplifiers. Proper biasing is used to minimize crossover distortion.

Push-pull is also used in switching power supplies. In push-pull converters, two switches alternately apply voltage to a transformer or inductor, typically via a center-tapped winding. This arrangement can improve transformer utilization and reduce ripple, but requires careful timing and drive circuitry.

In mechanical systems, push-pull describes dual-acting devices that move in both directions, such as double-acting pneumatic or hydraulic actuators, or bidirectional linear actuators. It can also describe user interfaces where a control action is achieved by pushing or pulling.

In agriculture, push-pull refers to pest-management strategies that use a repellent intercrop and a trap crop to push pests away from the main crop and attract them to a designated area. This approach has been studied for cereals and other staples to boost yields and reduce chemical inputs.

Across fields, the term push-pull signals paired opposing actions to achieve smooth, efficient, or controlled operation. Its meaning depends on context, from electronics and power conversion to mechanical actuation and pest management.