An isolation amplifier is a device which can measure the voltage between two terminals while maintaining a physical barrier between the test points and the terminal at which the measured voltage is presented.

Isolation amplfiers are typically used in the following situations.

• The terminals under test are hazardous live terminals.
• The terminals under test are high voltage relative to the local earth (ground) voltage.
• The common mode voltage of the terminals under test exceed the limits of other measurement equipment.
• Net current flowing between the unit under test and the measring intrumentation is undesirable.

Note that many Fylde products have a high common mode range and / or high input impedance with excellent common mode rejection properties. In general such amplifiers will give superior performance to isolation amplifiers although the safety of the measurement installation must always be the primary consideration.

FE-560-IA

The FE-560-IA is a high voltage isolation amplifier and attenuator providing galvanic isolation of up to 1.5 kV isolation between signal earth and output earth. The amplifier has gains from 1/100 up to x 100 with gain accuracy typically +/-0.1% for all steps. Isolation mode rejection is better than 150 dB (at gain 100). A 3 pole active filter is included, set by a plug in resistor network, the isolation amplifier is capable of operation up to 50kHz.

FE-460-IA

For up to 3.5 kV isolation this is a single channel module with precise accuracy of measurement and high bandwidth. The FE-460-IA is an isolated instrumentation amplifier which is usually used when the differential signal is small but is associated with a high common mode voltage. The module can be combined with a precision high voltage attenuator when the signal range is large.