Oscilloscope Octopus

This is part of a all-in-one unit I am building for my scope. After going through the different parts I plan to use I’ll soon enough will create a whole unit.

You can test components with a Oscilloscope the same way you would use a multi meter or a LCR meter. Instead of a numerical readout you use a Lissajous pattern.

Here is a typical set of Lissajous patterns that a Octopus circuit produces for a readout.


In a nut shell to test a part you just compare it to a known working part. Sometimes you can even test the part still in circuit.

I am not sure if this can be done on DSO style scopes but it can be done on analog scopes that have a XY function.

To build one you just need a total of four to five parts.

A wall wart AC adapter that outputs 6 to 8 volts AC. Not DC! If anything you can cut open a 9volt DC wall wart and remove the diodes and cap.
560 ohm 1/2watt resistor
100 ohm 1/2 watt resistor
1K ohm 1watt resistor


Just note the scope’s probe grounds connect the the ground end of the 1K resistor. Also some analog scopes already have a built in “component tester”. However even with this circuit you can zoom in and out to get better resolution.

To use the circuit correctly both of the scope’s channels have to be on the same settings for the Volts per Division.

Tomorrow I’ll add another post on a capacitor ESR tester.

All schematics for this post came from jammarcade.net



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