Mullard Pupil's Oscilloscope

by Parcgwyn in Circuits > Electronics

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Mullard Pupil's Oscilloscope

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This instructable describes the construction of a extremely simple 12v oscillosope.

The diagram below is a schematic of the Mullard pupil's oscilloscope.  This is a single valve (+CRT) oscilloscope that is about as simple as an oscilloscope can get.  The Mullard scope is described in the Radio Basics column of Practical Wireless March 2005.

Transformer Winding

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The transformer was home wound on a ferrite core that I had handy and an aluminium clamp fabricated to enable it to be fixed to the chassis.

Transformer Winding Details:
L1,L4 12 turns 26 swg
L2,L3 3 turns 26 swg
L5 450 turns 36 swg

Construction

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Below are pictures of the oscilloscope during construction and completed.  The scope shown above did not include the X attenuator potentiometer shown in the circuit diagram.  I also added a 68pF capacitor between the Y amplifier anode and the supressor grid of the timebase pentode to provide a sync. signal.