N2791A 25 MHz and N2891A 70 MHz High-Voltage Differential Probes User’s Guide For Safety, Regulatory, and publishing information, see the pages at the back of this book. © Copyright Agilent Technologies 2009 All Rights Reserved.
Contents Inspecting the Probe 3 Cleaning the Probe 3 Handling the Probe 3 N2791A/N2891A High-Voltage Differential Probes 4 Contents and Accessory Kits 5 Characteristics and Specifications 7 Safety Information 9 Using the N2791A High-Voltage Differential Probe 10 Using the N2891A High-Voltage Differential Probe 11 N2791A Plots 12 N2891A Plots 16 Using the Accessories 20 2
Inspecting the Probe Inspecting the Probe o Inspect the shipping container for damage. Keep the damaged shipping container or cushioning material until the contents of the shipment have been checked for completeness and the probe has been checked mechanically and electrically. o Check the accessories. • If the contents are incomplete or damaged, notify your Agilent Technologies Sales Office. o Inspect the instrument.
N2791A/N2891A High-Voltage Differential Probes N2791A/N2891A High-Voltage Differential Probes The N2791A/N2891A high-voltage differential probes allow conventional earthgrounded oscilloscopes to be used for floating signal measurements (up to 700 V of differential or common mode voltage for the N2791A and up to 7000 V of differential or common mode voltage for the N2891A).
Contents and Accessory Kits Contents and Accessory Kits The following table lists the parts included with the N2791A high-voltage differential probe. Part N2791A 25 MHz differential probe Safety Hook, Red Safety Hook, Black Alligator Clip, Red Alligator Clip, Black USB Power Cord (2 m) AA Battery User’s Guide Quantity 1 1 1 1 1 1 4 1 For N2791A replacement accessories, you can order the N2791-68700 Differential Probe Accessory Kit.
Contents and Accessory Kits The following table lists the parts included with the N2891A high-voltage differential probe. Part N2891A 70 MHz differential probe Safety Hook, Red Safety Hook, Black High Voltage Alligator Clip, Red High Voltage Alligator Clip, Black USB Power Cord (2 m) AA Battery User’s Guide Quantity 1 1 1 1 1 1 4 1 For N2891A replacement accessories, you can order the N2891-68700 Differential Probe Accessory Kit.
Characteristics and Specifications Characteristics and Specifications Characteristics and specifications for the N2791A and N2891A high-voltage differential probes are shown below. The probe / oscilloscope should be warmed up for at least 20 minutes before any testing and the environmental conditions should not exceed the probe’s specified limits.
Characteristics and Specifications Mechanical Characteristics Weight (probe only) BNC Cable Length Length of Input Leads Dimensions (L x W x H) N2791A 400 g (probe and PVC jacket) 95 cm (37 inches) 45 cm (18 inches) 170 mm x 63 mm x 21 mm (6.7 inches x 2.5 inches x 0.83 inches) N2891A 500 g 90 cm (35 inches) 60 cm (24inches) 202 mm x 83 mm x 38 mm (8.0 inches x 3.3 inches x 1.
Safety Information Safety Information Warning ! To avoid personal injury and to prevent fire or damage to this product or products connected to it, review and comply with the following safety precautions. Be aware that if you use this probe assembly in a manner not specified, the protection this product provides may be impaired.
Using the N2791A High-Voltage Differential Probe Do Not Operate With Suspected Failures If you suspect there is damage to this probe, have it inspected by a qualified service personnel. Using the N2791A High-Voltage Differential Probe • To use this probe, first insert the four AA batteries into the probe or connect the USB power cord to the probe and a USB port (see page 4 to see where the USB power cord input is located on the probe).
Using the N2891A High-Voltage Differential Probe ! ! • Using the appropriate probe accessories, connect the inputs to the circuit under test. To protect against electrical shock, use only the accessories supplied with this probe or in the accessory kit. This probe is to carry out differential measurements between two points on the circuit under test. This probe is not for electrically insulating the circuit under test and the measuring instrument.
N2791A Plots N2791A Plots 1.2 1 0.8 Step Input Signal Volts 0.6 Measured Step Response (17 ns 10-90% rise time) 0.4 0.2 0 -0.2 -100 -50 0 50 100 150 Time (ns) Graph of normalized step response (50, 16.5 ns rising edge step generator), 17 ns normalized rising edge (10-90%), 10:1 attenuation 1.2 1 0.8 Step Input Signal Volts 0.6 Measured Step Response (17 ns 10-90% rise time) 0.4 0.2 0 -0.
N2791A Plots 5 Vout/Vin dB 0 -5 -10 Vin -15 -20 Vout 0 1 10 10 Frequency (MHz) Graph of dB(Vin), dB(Vout) + 20dB, and dB(Vout/Vin) + 20dB frequency response, 10:1 attenuation 5 dB Vout/Vin 2.5 0 -2.5 Vout -5 -7.
N2791A Plots -20 dB-40 -60 -80 -100 2 10 3 10 4 5 10 6 10 10 7 10 8 10 Frequency (Hz) Graph of dB(Vout/Vin) + 20dB frequency response when inputs driven in common mode (common mode rejection), 10:1 attenuation 5 10 4 10 22 pF 3 10 2 10 6 10 7 10 8 10 9 10 Frequency (Hz) Magnitude plot of probe input impedance versus frequency (single-ended mode) 14
N2791A Plots 1100 900 Vrms 700 500 300 100 6 10 7 10 Frequency (Hz) Typical derating plot of the absolute maximum input voltage in common mode 15
N2891A Plots N2891A Plots 1.2 Step Input Signal Normalized Step Response (V) 1 0.8 0.6 Probe Step Response (10 ns 10-90% rise time) 0.4 0.2 0 -0.2 -20 0 20 40 Time (nS) 60 80 100 Graph of normalized step response (50 W, 10 ns rising edge step generator), 10 ns normalized rising edge (10-90%), 100:1 attenuation 1.2 Step Input Signal Normalized Step Response (V) 1 0.8 0.6 0.4 Probe Step Response (10 ns 10-90% rise time) 0.2 0 -0.
N2891A Plots 5 0 Normalized S21+40dB -5 -10 -15 -20 -25 -30 -35 0 10 2 4 10 10 Frequency Hz 6 8 10 10 Graph of dB (S21) + 40 dB frequency response, 100:1 attenuation 4 2 Normalized S21+60dB 0 -2 -4 -6 -8 -10 -12 -14 -16 0 10 2 10 4 10 Frequency Hz 6 10 8 10 Graph of dB (S21) + 60 dB frequency response, 1000:1 attenuation 17
N2891A Plots -10 -20 -30 CMRR dB -40 -50 -60 -70 -80 -90 2 4 10 6 10 8 10 10 Frequency (Hz) Graph of dB (S21) + 40 dB frequency response when inputs driven in common mode (common mode rejection), 100:1 attenuation 10 10 9 10 Input impedance (Ohms) 8 differential 10 5 pF single-ended 7 10 6 10 7.
N2891A Plots 10 4 Vrms 10 10 3 2 1 10 5 10 10 6 10 7 10 8 Frequency (Hz) Typical derating plot of the absolute maximum input voltage in common mode Input impedance equivalent circuit diagram 19
Using the Accessories Using the Accessories The accessories supplied with the N2791A and N2891A probes are attached by pushing them onto the probe leads as shown below. probe lead hook or clip The following accessories are supplied with the N2791A probe and with the N2791-68700 Accessory Kit.
Using the Accessories 21
