Instructions

AP033 Active Differential Probe

Continuous, with 1:15 weighting, of Channel 3. Turn off the trace 3 display. Use the

Math Zoom and Position controls as necessary to view the waveform.

12. Adjust ÷ CMRR (R7) for minimum amplitude. (See Figure 10 for location.)

13. Remove the BNC cable from the output of the Function Generator and the calibration

fixture. Leave the BNC cable from the SYNC output to the oscilloscope external

trigger input in place. Remove the BNC cable and 50Ω terminator from Channel 3.

E. Adjust OFFSET (R330)

1. Set AP033 probe Attenuation to /1 and Gain to X1. Set the Channel 1 scale factor to

2 mV/div, and the acquisition mode to Auto. Set the BWL to 20 or 25 MHz . Adjust

the OFFSET to 0.0 mV.

2. Carefully move the AP033 probe tip from the Common Mode Drive No Termination

position of the AP033 Calibration Fixture to the Differential Drive No Termination

position. Press the probe into the fixture to fully engage the pins.

3. Attach the female BNC to dual male banana plug adapters to each end of the BNC

cable. Plug one end into the output of the DC voltage source, making sure that the

plug corresponding to the BNC shield (marked “Ground”) is connected to the voltage

source – output (or common for dual supplies) connector, and the other pin on the +

output connector.

4. Connect the other end of the cable to the DMM input, making sure that the plug

corresponding to the BNC shield (marked “Ground”) is connected to the LO or COM

input.

5. Set the DC Voltage Source to read as close as possible to +0.4000 V on the DMM.

6. AutoZero the AP033.

7. Disconnect the BNC cable from the female BNC-to-dual male banana plug adapter on

the DMM.

8. Reconnect the BNC cable from the DC Voltage Source to the Differential Drive No

Termination connector on the AP033 Calibration Fixture.

9. Set the probe offset to –0.4000 V.

10. Allow 10 seconds for the AP033 to stabilize.

11. Adjust Offset (R330) to bring the trace back to exactly center screen. (See Figure 11.)

12. Remove the dual banana plug adapter from the output of the DC voltage source and

reconnect it, with the pins reversed. (The plug corresponding to the BNC shield

(marked “Ground”) should now be connected to the + Output connector.)

13. Set the probe offset to +0.4000 V.

14. Allow 10 seconds for the AP033 to stabilize.