R: Difference between revisions

The Tektronix Type R is a plug-in for 500-series oscilloscopes.  It is designed to measure risetime of a NPN and PNP transistors, but it works well with FETs as well.  It can operate in grounded-emitter or grounded-base configurations.  In the grounded-emitter configuration, it provides a variable collector voltage through a collector resistor which is used to sense the collector current.  It provides a base bias voltage and a base pulse signal, fed to the base of the transistor through a resistor.  The rise time of the base pulse is specified to be less than 5 nanoseconds.  Everything can be set independently.  The collector signal is AC-coupled to an amplifier whose output is fed to the oscilloscope.  The Type R has its own on-board low-voltage, high-current regulated power supplies which feature germanium power transistors.