# Demo measurement with handheld oscilloscope

#### Gillian Spiessens

Joined Feb 24, 2018
3
hey, in school we got the assignement to discuss a measuring divice. I have a fluke 192 handheld oscilloscope. One part of the assignement is to do a demo measurement that shows the strengths of this device. I have already done a measurement on a bridge rectifier to show the usefulness of the isolated inputs. But this was not good enough for the teacher. But we are allowed to continue working with this circuit but we have to make it a bit more interesting/difficult.

Would anyone have suggestions for what we can do?

This are some specs of the handheld oscilloscope:
• 60 MHz bandwith (DC coupled)
• Lower frequency limit, AC coupled: 10:1 = < 2Hz & 1:1 = < 5Hz
• Sensitieve ranges: 10:1 = 50mv to 1000V/Div & 1:1 = 50mv to 100V/Div
• Input impedance On BNC: 1Mohm// 15pF
• Trigger
• Record function

Joined Mar 10, 2018
4,057
Is teacher asking for DC and AC measurements ?

If latter diode datasheet typically has test circuit you can sue.

DC measurements done typically sweep I or V to a device to create
a plot, like -

If you do either swept test, especially reverse breakdown, make sure
you are using HV probes with scope, or make a V divider into scope
to make sure you don't blow out its front end amplifiers. Look at scope
manual for input V spec limits.

https://electronics.stackexchange.c...o-attach-safely-an-o-scope-to-various-sources

https://www.testandmeasurementtips.com/not-destroy-oscilloscope/

https://literature.cdn.keysight.com/litweb/pdf/54919-92006.pdf?id=2939944&cc=RU&lc=rus

https://users.wpi.edu/~sjbitar/ece2201/lab/ece2201_sjb_lab1.pdf

Regards, Dana.

#### Hymie

Joined Mar 30, 2018
1,082
If the bridge rectifier circuit is not referenced to earth, then any scope could manage these measurements. So one of the main strengths of such a scope is measurements within circuits where the circuit cannot easily be isolated from earth – such as a mains circuit. (which would otherwise require a differential probes or powered via an isolation transformer).

The scope also has measurement functions and maths functions (besides those you list, including record function).

Therefore you should be considering using both channels, trigger, measurement and record functions – together with demonstrating the maths capabilities.

You might have to build simple circuit (such as a 555 astable circuit) for demonstration purposes. I would recommend that you do not use a mains circuit for demonstration purposes, given the potential hazards involved.