What is a BR2 connector?
The outer dimensions and style of connection action of the BR2 connector are identical to BNC. However, instead of one centre pin, the BR2 has two inner pins beside each other (with the shielding braid around both of them). The use of BR2 connectors and shielded, twisted pair cable reduces noise considerably when measuring remote current sources in a noisy environment.
How can I measure a grounded source?
In order to measure a grounded source, the amplifier must have a single ended input configuration. You may use either the BNC or BR2 receptacle.
What is a differential input?
Often we think of a current source as having only one connection, however the other connection is just as important: it is the current return path. A differential input has an active amplifier input for both connection points to the current source. The outputs of these two amplifiers are then electrically subtracted. This has the effect of doubling the signal voltage (since the return path current is of opposite polarity), but cancels any noise components which were equal on both electrodes (“common mode” noise).