3B3: Difference between revisions

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The Tektronix Type 3B3 is sweep unit [[introduced in 1963]], intended for use with the 561A.
The Tektronix Type 3B3 is sweep unit [[introduced in 1963]], intended for use with the [[561|561A]].
It works fine in other 560-series scopes.
It works fine in other [[560-series scopes]].
It provides a calibrated delay from 500 nsec to 10 seconds after the trigger event, before
It provides a calibrated delay from 500 nsec to 10 seconds after the trigger event, before
sweeping.  Delayed sweep allows the operator to "zoom in" on regions of interest in a waveform.
sweeping.  Delayed sweep allows the operator to "zoom in" on regions of interest in a waveform.
The 3B3 provides an intensified mode that indicates the selected region of interest in the  
The 3B3 provides an intensified mode that indicates the selected region of interest in the  
delayed sweep by showing the entire waveform with the trace brighter in the selected region.
delayed sweep by showing the entire waveform with the trace brighter in the selected region.
Triggering is done using a 2mA germanium tunnel diode.  The trigger source is buffered by
Triggering is done using a 2mA germanium [[tunnel diodes|tunnel diode]].  The trigger source is buffered by
a 7895 Nuvistor triode cathode-follower driving a differential amplifier formed by two
a [[7895]] Nuvistor triode cathode-follower driving a differential amplifier formed by two
2N2207 germanium PNP transistors.  The collector current switches the tunnel diode when
[[2N2207]] germanium PNP transistors.  The collector current switches the tunnel diode when
a triggering event occurs.
a triggering event occurs.
* [http://bama.edebris.com/download/tek/3b3/3b3.djvu Tektronix 3B3 Manual (DjVu)]
* [http://w140.com/3b3.pdf Tektronix 3B3 Manual (PDF)]


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