Ivan Vegvary wrote:


"Peak-to-Peak" meter.
For what are (were) they used? Got it for free.
Is it simply so I don't have to multiply by 1.414?


** A clue is the graphic on the front of the unit - it shows a typical sweep waveform from a TV set. TV service manuals are often full of such diagrams, accompanied by p-p voltage values.

http://www.boxcarcabin.com/PhilcoPre...ematicBoth.jpg

A service tech might need to measure the ones he finds in a set, but has not got a calibrated scope - just a basic CRT based waveform monitor.

So he uses the Senco to produce a 60Hz sine wave with the same p-p height on the screen of his monitor - then measures that with a regular multimeter and multiplies the result by 2.82.

A similar trick can be used when calibrating the vertical display of a scope using just a DC source and a DMM. Set the scope to DC coupled and apply a voltage to the input while monitoring same on the DMM.

Most DMMs have better than 1% accuracy on DC volts so you simply adjust the scope's internal cal trimmer to match the full scale deflection ( usually 8 divs ) on the screen.

Square waves can then be used to check the scope's vertical response for flatness.



..... Phil