Re: Oscilloscope arrived - black market sucks

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Original poster: Kreso Bukvic <kreso.bukvic-at-kc.htnet.hr> 

I know how to work with oscilloscope but i think that CRT is in defect

Il explain latter GTG

Beszt Regards

Kreso Bukvic
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, April 05, 2004 3:29 PM
Subject: Re: Oscilloscope arrived - black market sucks


 > Original poster: David Speck <dave-at-davidspeckmd-dot-org>
 >
 > Kreso,
 > It sounds like your scope is actually working OK, especially if you have a
 > recognizable trace on the screen.
 >
 > Your nine volt output transformer is the output rating under its designed
 > load.  The scope presents nearly no load, so the voltage will probably be
 > higher. Further, the specs on small transformers are usually pretty loose,
 > and if your line voltage is high, you'll also read high.
 > Also, you have to remember that the scope is showing peak to peak values,
 > which will be 1.414 * 9 volts, or 12.7 volts.  With all these factors
 > considered, the displayed trace sounds about right.
 >
 > Scope have a very high impedance input, and will pick up all sorts of
 > interference from the air.  It's perfectly normal to see a trace on the
 > screen if you have an open wire connected to the input.  If you touch the
 > wire, the trace will increase as your body will add to the antenna effect.
 >
 > I'm not sure how you connected the diodes. but it you wire a correct diode
 > bridge, with a 10K ohm resistor for a load, you should see a proper
 > pulsating DC waveform.
 >
 > Keep at it.  Scopes actually display what is out there, which is not
always
 > the same as you would think from working with paper circuits.
 > Try to find someone experienced with electronics who can help you learn to
 > use the unit.
 >
 > Dave
 > ====+====+====+====+====+====+====+====+====+====+====+====
 > I tried conecting 9 VAC transformer at input, scope measures 15 V with odd
 > showing, ok i tried adding one diode no improwment 2 dioes nothing, greatz
 > then i get only a line it cannot be a line only with a greatz - right? It
 > cannot be full DC with only 4 diodes? Or when i touch the table the
waveform
 >
 > >gose here and there it moves by it self, scope is not fizically connected
to
 > >table it does  alot of crap etc and etc.
 >
 >
 >
 >
 >
 >
 >