Source measurement unit
Encyclopedia
The Source–measurement unit (SMU) is a type of test equipment which, as the name indicates, is capable of both sourcing and measuring at the same time.
or as a constant voltage source
. It simultaneously sources to a pair of terminals
at the same time measuring the current or voltage across those terminals. Typically when an SMU sources constant voltage it measures current through the terminals. When it sources constant current through the terminals, it measures the voltage built up across those terminals.
SMUs are typically used in automatic test equipment
and they usually come with an interface such as GPIB
or USB
to enable connection to a computer.
Overview
The SMU is a special kind of instrument that can work as a constant current sourceCurrent source
A current source is an electrical or electronic device that delivers or absorbs electric current. A current source is the dual of a voltage source. The term constant-current sink is sometimes used for sources fed from a negative voltage supply...
or as a constant voltage source
Voltage source
In electric circuit theory, an ideal voltage source is a circuit element where the voltage across it is independent of the current through it. A voltage source is the dual of a current source. In analysis, a voltage source supplies a constant DC or AC potential between its terminals for any current...
. It simultaneously sources to a pair of terminals
Terminal (electronics)
A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener...
at the same time measuring the current or voltage across those terminals. Typically when an SMU sources constant voltage it measures current through the terminals. When it sources constant current through the terminals, it measures the voltage built up across those terminals.
SMUs are typically used in automatic test equipment
Automatic test equipment
Automatic or Automated Test Equipment is any apparatus that performs tests on a device, known as the Device Under Test , using automation to quickly perform measurements and evaluate the test results...
and they usually come with an interface such as GPIB
IEEE-488
IEEE-488 is a short-range digital communications bus specification. It was created for use with automated test equipment in the late 1960s, and is still in use for that purpose. IEEE-488 was created as HP-IB , and is commonly called GPIB...
or USB
Universal Serial Bus
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
to enable connection to a computer.