In audio engineering and sound recording, a high impedance bridging, voltage bridging, or simply bridging connection is one in which the load impedance is much larger than the source impedance.[1][2][3] The load measures the source's voltage while minimally drawing current or affecting it.
In all modern usage the microphone looks into an impedance in the 2000 ohm range or higher, and this represents what is called a bridging load, one which is effectively an open circuit load for the microphone.
A circuit where the input termination impedance is a minimum of some 10 times the source impedance of the output driving that input is said to be a bridging input
In the case of bridging systems, we say the source impedance is low and the load impedances are high