CenterTapped

Center-tapped refers to an electrical winding configuration in which a single winding is divided into two equal halves with a connection at the midpoint, the center tap. The outer ends provide voltages that are equal in magnitude and opposite in phase with respect to the center tap. This arrangement is common on transformer windings, particularly the secondary, though it can appear in other inductive components as well.

One common use is to create dual-polarity DC power supplies. By connecting the center tap to ground and using two diodes to rectify the two halves, a full-wave rectifier yields positive and negative rails with respect to ground. The center-tapped arrangement is also used in push-pull amplifier stages and in some audio and RF transformers to facilitate balanced operation, impedance matching, or drive from a single winding to two devices.

When designing a center-tapped winding, the turns on each half are kept equal, and the center tap is treated as a low-impedance reference node. The center tap may be connected to chassis or system ground. Leakage inductance and winding resistance influence regulation and transient response. Safety isolation remains provided by the transformer, but the center tap itself is an internal conductor that must be accounted for in circuit design.

Center-tapped windings remain common in power transformers for tube and switch-mode power supplies, audio transformers, and certain high-voltage applications, though some modern designs use alternative rectification or topology. The term center-tapped (or center-tapped) is used to describe this winding configuration.