SERIES VL

CURRENT VIEWING RESISTOR

(Series A, inline version - Series M, inline version with Voltage Divider plug added.)

DESCRIPTION

Series VL are inline CVR'S with a voltage divider added for simultaneous voltage and current measurements.

SPECIFICATIONS

The  electrical specifications are the same as the corresponding specification for the Series A and Series M respectively.

APPLICATIONS

In many studies involving pulse currents, simultaneous measurements of both current and voltage at the load are necessary.  Quite often, however, when measurements of this type are attempted, severe distortion of the monitored waveforms are observed.  Series VL resistors, in addition to providing a convenient and direct method of simultaneous measurement, are designed to eliminate major sources of wave form distortion.  Their completely coaxial design assures both a broad flat frequency response and component shielding.  Voltage Divider and CVR sections of the VL unit ground at a common point and thus ground loop-produced distortions are minimized.   CVR construction and operation of the VL resistor is similar to the Series L inline CVR.  When voltage is measured, the VL unit should be installed with the voltage monitor point immediately adjacent to the load to minimize lead inductance.  It should be noted that in this orientation the polarity of the output signal from the CVR will be opposite that of the input current and output voltage signals.  Also see Series L inline CVR for additional information.  When voltage signals are utilized only for timing or trigger functions, operations of the VL unit in the reversed orientation may be preferred, since not only is the output current signal in phase with the input current, but the possibility of an accidental short circuiting of the CVR resistive element by improper grounding is avoided.  The plug-in voltage dividers are resistance networks internally terminated in 50 ohms.  The voltage division ratio tabulated for each divider assumes that a 50-ohm coaxial line, terminated in its characteristic impedance at the oscilloscope, is utilized.  In some types of pulse circuitry there exists a possibility of the load becoming an open circuit during the discharge.  In this case the remaining stored energy must be dissipated in the resistance of the voltage divider.  For this reason the plug-in units of the VL resistor are constructed to sustain short term energy inputs up to 100 joules.  If the maximum rating is exceeded, however, a change in the attenuation ratio or actual destruction of the divider may result.