Amplifying repeaters merely amplify the signal, distortions and all. They make no attempt to correct distorted messages. Repeaters work on Layer 1 and serve only to extend the physical length of a network. They divide a large network into smaller segments and isolate the segments from each other, thus reducing contention. Bridges keep traffic separate within segments, and transfer data across segments when needed.
Bridges also regenerate weak signals.
Bridges may also be single port, which connect two segments, or multiport which connect several segments. When a bridge sees a packet, it checks the packet's destination address against its internal list. If the address indicates the packet needs to be forwarded to another segment, it passes the packet to the other segment. If the bridge doesn't know where the receiving station is located, it sends it to the other segment anyway. Changes in the network require that the bridge be re-programmed.