Digital buffer

A digital buffer (or a logic buffer) is an electronic circuit element used to copy a digital input signal and isolate it from any output load. For the typical case of using voltages as logic signals, a logic buffer's input impedance is high, so it draws little current from the input circuit, to avoid disturbing its signal.

The digital buffer is important in data transmission between connected systems. Buffers are used in registers (data storage device) and buses (data transferring device). To connect to a shared bus, a tri-state digital buffer should be used, because it has a high impedance ("inactive" or "disconnected") output state (in addition to logic low and high).