Instructables

Mullard Pupil's Oscilloscope

Picture of Mullard Pupil's Oscilloscope
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.
 
Remove these adsRemove these ads by Signing Up

Step 1: Transformer Winding

Picture of Transformer Winding
t1b.jpg
t1c.jpg
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

Step 2: Construction

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.
robot7979 months ago
how much volts on the high voltage?
Parcgwyn (author)  robot7976 months ago
Sorry for the late reply, I think it is about 275 to 300V.
I like this.

Where did you get the cathode tube?

All of mine are over a foot long and six inches wide.

Have you seen my Instructable, Building a Digital Oscilloscope from a DIY Kit?

http://www.instructables.com/id/Building-a-Digital-Oscilloscope-from-a-DIY-Kit/
002.JPG
Parcgwyn (author)  Josehf Murchison1 year ago
Hi Josehf,
I purchased the cathode ray tube from ebay for about £15 in the UK an alternative to dh3-91 is the 1cp1. Thanks for the link to your page I have seen this kits advertised and may buy one in the future.
Cool I was looking at another Instructable they got there tube from an old video camera.