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Making noise

V

V8TR4

Jan 1, 1970
0
Hi everyone,

I am working with a lot of TTL circuits in a lab enviroment and noise is
always a huge issue. Mostly noise from ION souces and Electron beam guns
when they short out. I am looking for a way to test my circuits in an
enviorment like this. Currently I find I get good results from unplugging a
transformer with a load on it. The inductive kick can be seen rattling the
shift registers. I was wondeirng what other things I could do to bring some
noise into my circuits. I am thinking right now to simply use a 208 to 24v
(60amp) transformer I have extra and put a good 12 volt load on it since I
will only be inputting 110. I will put a relay or switch to break the
circuit.

Should I break both poles or is just disconnecting one pole good enough?

Any other means out there to create noise for testing circuits from noise?

Thanks,

Oliver
 
T

Tom Woodrow

Jan 1, 1970
0
heat guns, old ac drill motors, spark gaps, these are just a few that
come to mind from the early 70's when were testing Commodore desktop
calculators.

Tom Woodrow
www.dacworks.com
 
T

The real Andy

Jan 1, 1970
0
I have many times used a few different sized relays wired up as buzzers.
Dont grab them powerleads though, give you a nice tingle. Good for the odd
practical joke on the apprentice!!
 
D

default

Jan 1, 1970
0
Hi everyone,

I am working with a lot of TTL circuits in a lab enviroment and noise is
always a huge issue. Mostly noise from ION souces and Electron beam guns
when they short out. I am looking for a way to test my circuits in an
enviorment like this. Currently I find I get good results from unplugging a
transformer with a load on it. The inductive kick can be seen rattling the
shift registers. I was wondeirng what other things I could do to bring some
noise into my circuits. I am thinking right now to simply use a 208 to 24v
(60amp) transformer I have extra and put a good 12 volt load on it since I
will only be inputting 110. I will put a relay or switch to break the
circuit.

Should I break both poles or is just disconnecting one pole good enough?

Any other means out there to create noise for testing circuits from noise?

Thanks,

Oliver
Tesla coil.
 
K

Klaus Vestergaard Kragelund

Jan 1, 1970
0
V8TR4 said:
Hi everyone,

I am working with a lot of TTL circuits in a lab enviroment and noise is
always a huge issue. Mostly noise from ION souces and Electron beam guns
when they short out. I am looking for a way to test my circuits in an
enviorment like this. Currently I find I get good results from unplugging a
transformer with a load on it. The inductive kick can be seen rattling the
shift registers. I was wondeirng what other things I could do to bring some
noise into my circuits. I am thinking right now to simply use a 208 to 24v
(60amp) transformer I have extra and put a good 12 volt load on it since I
will only be inputting 110. I will put a relay or switch to break the
circuit.

Should I break both poles or is just disconnecting one pole good enough?

Any other means out there to create noise for testing circuits from noise?

Turning on a mobile phone and placing it in close proximity of the circuit.

Using a lighter - the ones that light up with a piezo (I think) pushbutton

Cheers

Klaus
 
F

Frank Bemelman

Jan 1, 1970
0
An old electric coffee grinder, with the filter caps (if any) removed.
 
F

Fred

Jan 1, 1970
0
V8TR4 said:
Hi everyone,

I am working with a lot of TTL circuits in a lab enviroment and noise is
always a huge issue. Mostly noise from ION souces and Electron beam guns
when they short out. I am looking for a way to test my circuits in an
enviorment like this. Currently I find I get good results from unplugging a
transformer with a load on it. The inductive kick can be seen rattling the
shift registers. I was wondeirng what other things I could do to bring some
noise into my circuits. I am thinking right now to simply use a 208 to 24v
(60amp) transformer I have extra and put a good 12 volt load on it since I
will only be inputting 110. I will put a relay or switch to break the
circuit.

Should I break both poles or is just disconnecting one pole good enough?

Any other means out there to create noise for testing circuits from noise?

Thanks,

Oliver

Many years ago I had a very noisy neighbour and he would listen to what was
then Radio 2 on the long wave, 198m. I got a triac, a diac and a 1.0uF
polypropylene(?) capacitor and generated some massive spikes on the mains.
Completely drowned out the radio. The spikes were so harsh that you could
see a horizontal ripple on a TV.

I was thinking of using a thyristor next since these turn on faster in the
centre of a bridge diode but never got round to it :-(
 
J

JeffM

Jan 1, 1970
0
relays wired up as buzzers

Yup. Very cheap. Very effective.

The bigger, the better.
 
R

R.Legg

Jan 1, 1970
0
V8TR4 said:
Any other means out there to create noise for testing circuits from noise?


Weller WTCP soldering irons. I like them and find their magnetic
regulator and transformer on-off switch to be excellent spike
generators, at less than ten paces.

If you are serious, and have a spec and a budget, It's best to
characterize the fields for which you intend to provide immunity and
test your equipment using suitable calibrated EM field generators.

RL
 
T

tim kettring

Jan 1, 1970
0
Maybe a "plasma globe" that used to be popular around in the late 1980s .

tim
 
T

Terry Pinnell

Jan 1, 1970
0
V8TR4 said:
Any other means out there to create noise for testing circuits from noise?

I sometimes plug a DIY drill into nearby mains socker and switch it
on/off a few times. Alternatively, my old vacuum cleaner.
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
Any other means out there to create noise for testing circuits from noise?

If you actually want to *test* something, as opposed to kicking the tyres so
to speak, you need to have some reliable setup that will create the same
conditions on each test. Otherwise you will not know whether you are solving
problems or just got lucky passing the test.

When I did EMI trouble-shooting, we used a high frequency generator to
inject RF signals into the wires connected to the equipment and a power
meter to measure via a current transformer what the injection level was.
Then we swept the frequency across a defined band, noted any
responses/deviant behaviour from the equipment, increased the power for a
new sweep etc.

Boring and Tedious, but we did find and fix enough problems to totally
eliminate the "random failures" and "strange behaviour" seen in the
equipment.

PS:
It is not worth the effort to test for EMI sensitivity on a circuit on
itself; because you designed it correctly in the first place!?
One has to test the unit in the situation it is supposed to be used in to
get any meaningful results.
 
G

Guy Macon

Jan 1, 1970
0
V8TR4 said:
Hi everyone,

I am working with a lot of TTL circuits in a lab enviroment and noise is
always a huge issue. Mostly noise from ION souces and Electron beam guns
when they short out. I am looking for a way to test my circuits in an
enviorment like this. Currently I find I get good results from unplugging a
transformer with a load on it. The inductive kick can be seen rattling the
shift registers. I was wondeirng what other things I could do to bring some
noise into my circuits.

I use a Jacobs Ladder and a Tesla Coil not only do they generate lots
of noise, they also impress the managers.
 
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