Antiparallel (electronics)

In electronics, the term "antiparallel" describes a configuration where two identical components are connected in parallel but with opposite polarities. This arrangement is most commonly applied to diodes, but can, in principle, be used with other two-terminal devices.

When two diodes are connected in antiparallel, one diode conducts current when the voltage across the pair is positive, and the other conducts current when the voltage is negative. The voltage drop across the conducting diode is relatively constant, typically around 0.7 volts for silicon diodes, acting as a clamping circuit. This clamping effect limits the voltage across the pair to approximately +/- 0.7 volts.

This configuration is frequently used for surge protection, preventing a voltage from exceeding a certain level. It can also be used to approximate a resistor with a non-linear voltage-current characteristic, where the current increases rapidly as the voltage approaches the forward voltage of the diodes. The symmetry of the antiparallel connection is key to its function.