3B1: Difference between revisions

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The Tektronix 3B1 is a timebase plug-in [[introduced in 1962]] for [[560-series scopes]].   
The Tektronix 3B1 is a timebase plug-in [[introduced in 1962]] for [[560-series scopes]].   
10MHz is is the maximum trigger frequency.
10MHz is is the maximum trigger frequency.
The calibrated sweep rates go from 1 sec/div to 500 nsec/div.
The calibrated sweep rates go from 1 s/Div to 500 ns/Div.
There is a switch that enables 5X horizontal magnification,  
There is a switch that enables 5 × horizontal magnification,  
which makes the fastest sweep 100 nsec/div.  The 3B1 has a delayed sweep
which makes the fastest sweep 100 ns/Div.  The 3B1 has a delayed sweep
and a regular sweep.  The 3B1 uses vacuum tubes, bipolar junction transistors,
and a regular sweep.  The 3B1 uses vacuum tubes, bipolar junction transistors,
and [[tunnel diodes]].
and [[tunnel diodes]].
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compares the sweep ramp voltage with a knob-controlled
compares the sweep ramp voltage with a knob-controlled
DC voltage which determines the point where the delayed trigger starts.   
DC voltage which determines the point where the delayed trigger starts.   
The DC voltage is made by a [[ZZ1000]] 80V reference passed through  
The DC voltage is made by a [[ZZ1000]] 80 V reference passed through  
a potentiometer-variable voltage divider.   
a potentiometer-variable voltage divider.   
When the sweep ramp exceeds the control voltage, a 2.2mA tunnel diode in the
When the sweep ramp exceeds the control voltage, a 2.2 mA tunnel diode in the
plate load of the differential amplifier switches state.
plate load of the differential amplifier switches state.


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File:3b1 horizontal amp.png|Horizontal amp circuit
File:3b1 horizontal amp.png|Horizontal amp circuit
</gallery>
</gallery>
[[Category:560 series plugins]]

Revision as of 07:22, 29 June 2014

The Tektronix 3B1 is a timebase plug-in introduced in 1962 for 560-series scopes. 10MHz is is the maximum trigger frequency. The calibrated sweep rates go from 1 s/Div to 500 ns/Div. There is a switch that enables 5 × horizontal magnification, which makes the fastest sweep 100 ns/Div. The 3B1 has a delayed sweep and a regular sweep. The 3B1 uses vacuum tubes, bipolar junction transistors, and tunnel diodes.

The trigger input goes through the int/ext switch and then the ac/dc coupling switch, and then a 7895 cathode follower. The output of the cathode follower drives one base of a 2N2207 PNP differential amplifier which has a tunnel diode in the collector load. The tunnel diode generates pulses when it switches back and forth between its two stable voltages, which are capacitively coupled to a 2N2501 NPN common emitter amplifier.

The delay pickoff circuit is a 6DJ8 differential amplifier that compares the sweep ramp voltage with a knob-controlled DC voltage which determines the point where the delayed trigger starts. The DC voltage is made by a ZZ1000 80 V reference passed through a potentiometer-variable voltage divider. When the sweep ramp exceeds the control voltage, a 2.2 mA tunnel diode in the plate load of the differential amplifier switches state.