9 Jun
2006
9 Jun
'06
4:41 p.m.
woodelf wrote:
Remembr it's hard to read any analogue 'scope to better than 1%. so your
'standards' don't need to be very accurate. The average 4-pin crystal
oscillator can has, I beleive, a tolerance of 200ppm at a specified
temperature (20C?) and isn't that far out at normal room temperatures.
That is easily good enough to set up a 'scope.
Ditto for voltage. Maxim (I think) make a range of bandgap reference ICs
that are more accurate than any normal 'scope. Wire one up in the
standard circuit and use that.
Wolfe, Julian wrote:
> Hi all,
>
> I'm going to go to a hamfest this weekend to look for an oscilloscope.
>
unless you get a digital scope that holds calibration well, you will
probably be wise to pick up a frequency reference, and voltage
refreence to calibrate them with, unless you have access to such
somewhere outside your home shop, such as at work.
If you have a standalone operation, being able to check the
voltage and triggering on your scope and recalibrate them
is desirable too. a lot of bargain scopes will put up a
nice square wave, especially tektronics showing the internal
test square wave, and wont trigger on the crap you really
see in your old computers worth a crap.
Odd. I've always found Tektronix triggering to be the best around. Which
is more than I can say of a Hameg I used once. It couldn't trigger on the
index pulse from an RK05 (a nice, clean, TTL signal).
-tony