9758B DC Electronic Load Module

Mô tả

The 9758B electronic load module works by putting a required DC load across a power source under test. It can be also be used to investigate the behaviour of many different types of power source such as batteries, solar cells, fuel cells or wind generators, as well as electronic power supply units. Comprehnsive features include:

Multiple Modes of Operation
Constant Current: Constant current mode is used for load testing of normal voltage source power supplies and for constant current discharge testing of batteries. This mode provides rapid measurement of power source regulation (V/I characteristics).

Constant Voltage: Constant voltage mode is used for load testing of constant current power supplies. The unit operates as a high power shunt regulator.

Constant Power: Constant power mode simulates a load whose power consumption is independant of the applied voltage. This is true of many types of equipment that incoporate switchmode regulators. This mode may be particularly suitable for testing power sources of portable devices such as Lithium-ion batteries.

Constant Resistance: Constant resistance mode simulates a standard resistive load by providing a current drain proportional to voltage. Settings are displayed in Ohms or milli-Ohms. Unlike fixed resistors or rheostats, the load provides a precisely controllable resistance with high power dissipation over a wide value range.

Constant Conductance: Constant conductance (CG) mode is also incorporated. As well as showing settings in amps per volt, this mode provides better resolution when setting very low equivalent resistance values.

Adjustable Voltage Drop-Out
Some power sources, such as rechargeable batteries, can be damaged if their output voltage falls below a certain level. The 9758B provides automatic protection by incoprorating fully variable voltage dropout (CI, CR, CG and CP modes). If the voltage applied to the load falls below a preset level, the load current is rapidly reduced to zero.

Transient generator and variable slew
The 9758B incorporates a full variable frequency, variable duty cycle transient generator. Switching between the two preset levels can be done at any frequency between 0.1Hz and 10kHz. The transient generator can be used in all operating modes. The rate of change between levels (slew rate) is controllable over a wide range. Slew rate control applies to all changes of level including remote control and manual changes between level A and level B. A slow-start function can be selected for situations where latching would otherwise occur at switch-on.

High resolution setting and measurement
The levels for each operating mode are set using high quality ten turn potentiometers for both level A and level B. Levels are displayed using four digit meters which provide resolution down to 1mA, 1mV and 1mΩ. Settings for slew rate, transient frequency, duty cycle and dropout voltage can also be displayed. In measurement mode the meters have an accuracy of 0.1% for voltage and 0.2% for current.

Current waveform monitor
It is often important to be able to observe the load current waveform on an oscilloscope. The 9758B provides a calibrated monitor output for this purpose as well as a sync output from the transient generator. The monitor output has several volts of compliance with respect to the load input, thus allowing it to be connected to a grounded oscilloscope without current divertion.

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