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trick to detecting clock?

N

N_Cook

Jan 1, 1970
0
Is there some way to detect a 3-5volt say khz clock using an ordinary
instrument(no osciloscope)

A crystal earpiece, assuming voltages not more than 50 volt.
A much underestimated piece of diagnostic test gear.
 
G

Gareth Magennis

Jan 1, 1970
0
Is there some way to detect a 3-5volt say khz clock using an ordinary
instrument(no osciloscope)


With a multimeter that measures frequency.



Gareth.
 
B

bz

Jan 1, 1970
0
Is there some way to detect a 3-5volt say khz clock using an ordinary
instrument(no osciloscope)

With a few ICs and LEDs you can build a logic probe with pulse detection.

http://www.eng.cam.ac.uk/DesignOffice/mdp/electric_web/Exper/EXP_7.html
has several interesting circuits, easy to build.

and for a 'delux' device
http://members.cox.net/berniekm/super.html





--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap
 
S

Sjouke Burry

Jan 1, 1970
0
Is there some way to detect a 3-5volt say khz clock using an ordinary
instrument(no osciloscope)
Buy a meter with freq. range. A lot of them are
equipped with that.
Mine(78Euro Extech)has Farad/Hertz/Farenheit/Celcius as
bonus ranges, temp is done with a termocouple.
 
N

N_Cook

Jan 1, 1970
0
Ron(UK) said:
One of the most useful bit of kit in my toolbox is a device I made
myself some 35 or so years ago. It`s a crystal earpiece with one wire
terminated in a croc clip and the other in a probe made from an old
ballpoint pen and a brass nail, there`s a capacitor in series to provide
DC blocking.
With this simple device I can trace audio through a circuit- from the
output of a crystal pick-up to several hundreds watts, I can detect
digital pulses, hear hum on a DC supply, etc. etc.

Ron(UK)

I must do the same sometime.
I've always picked up the standard earpiece and a pair of croc-leads and a
needle point rather than making a purpose built tool. Adding in a HV cap if
monitoring for noisy HT lines.
A scope would not show any more info in that situation and avoids
possibility of connecting scope up, in DC mode, set on 1mV/cm or HT pulse
transmitted through internal cap of scope, on a low range, and out goes dual
gate FET or whatever.
 
B

Blarp

Jan 1, 1970
0
must do the same sometime.
I've always picked up the standard earpiece and a pair of croc-leads and a
needle point rather than making a purpose built tool. Adding in a HV cap if
monitoring for noisy HT lines.
A scope would not show any more info in that situation and avoids
possibility of connecting scope up, in DC mode, set on 1mV/cm or HT pulse
transmitted through internal cap of scope, on a low range, and out goes dual
gate FET or whatever.

At home I have an old analog scope with "Y" output, onto which I
connected a simple amp+speaker.

The ticks / hums / squieks out of the speaker are extremely revealing
about what is measured; most of the time I do not need to look at the
screen at all.

In a cpu setup, one can even hear the software "run" on an adress
line (reoccurring sound patterns), and actually hear subroutines and
such.

At the office, the sophisticated DSO's no longer have this very useful
option..
 
R

Rich Webb

Jan 1, 1970
0
Audio monitoring of program execution was standard practice on large
computers for decades and for me is a sadly missed diagnostic of an
often more useful nature than flow graphs and trace dumps. Using
an AM or FM radio near programmed logic can sometimes provide similar
functionality.

Then there was the demo program supplied (on cassette tape, natch) by
The Digital Group for their Z80 systems, which "played" the Star
Spangled Banner all over the AM band to a nearby radio while
ASCII-arting a flag-like object on its 16x64 display. Way cool ...
 
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