quality of cheap 5 in 1 oscilloscope from ebay

Discussion in 'General Electronics Chat' started by ninjaman, May 5, 2016.

  1. ninjaman

    Thread Starter Member

    May 18, 2013

    i bought a 5 in 1 oscilloscope for £65 off ebay
    i have tried to make a diode clipper circuit and measure the 0.7 volts of the diode in both directions, cathode to ground and anode to ground. i did get a sine wave going positive with a -700mv (approx) and the other way i measured 400mv (approx)
    when i disconnected the probes there seemed to be some voltage measured on the screen. could this voltage be a calibration issue?
    the value is only small.
    this is the web page that i am using for the experiments
    i tried to measure the voltage of a single AA battery. i measured the battery with my multimeter and got 1.6 volts, the battery is brand new. then i measured the battery with the scope and got 1.2v
    not sure what is going on here.
    any help, is there a way that i could check the scope more accurately?

  2. BR-549

    Well-Known Member

    Sep 22, 2013
    I never used one of those pc scopes. Most regular scopes have a little calibration tab, you can attach your probe to.

    And most manuals have a calibration procedure.

    If you want your display to be like the link's examples......check your ac-dc mode settings.