Specifications

Setting the Current Limit:

1) Let's assume you have set the +6 V supply to 5.000V, and the display indicates you have the

+6 V supply selected. To set the current limit, press the Display Limit button, then the

Voltage/Current button. Use the control knob and the "Resolution Selection Keys" (the <

and > keys underneath the control knob) to adjust the current limit to 0.020 A.

2) This setting of 0.020 A means that no matter what you do, the current from the +6 V supply

(which is now set to 5.000 V) will never exceed 20 mA. Let's verify that two ways: with a

short circuit, and with an LED.

3) First, note the voltage and current displays: the voltage is very close to 5.000 V, and the

current is 0.000A (since nothing is connected to the + and - terminals of the 6 V supply).

Also, at the right side of the display a "CV" is showing; this means the supply is in "Constant

Voltage" mode, and will maintain 5.000 V unless the current reaches 20 mA, in which case

the output voltage will drop to whatever value is needed to keep the current at 20 mA.

4) Connect a jumper wire (or alligator lead) between the + and - terminals of the 6 V supply.

Note the voltage is 0.000 V, the current is close to 20 mA, and the "CV" has been replaced

by "CC" ("Constant Current").

5) Now let's try this with an inexpensive LED. Connect an LED with the anode to the plus

terminal, and the cathode to the minus terminal, of the 6 V supply (which is set to 5.000 V).

Normally, without current limiting, an LED will be quickly destroyed by this procedure. What

happens to your LED?

What is the output voltage (it should be around 2.0 V, depending on the color of the LED)?

What is the current (it should be near 20 mA). Your LED is emitting light, and will live to see

another day, because the current limiting circuit protected it by lowering the voltage.

6) If you don't mind destroying an LED, you can see the effects of not using current limiting.

Turn the power supply off, then turn it on again. Set the +6 V supply to 5.000 V, and again

connect the LED to the + and - terminals. What happened? LEDs will either burn out, or will

get really hot (don't burn yourself on the leads of the LED).

This power supply has many useful features, including remote control and the ability to store

and recall three setups from nonvolatile memory. Look in the Agilent manual for this instrument

for complete information.