Hi. Need help, don't understand why this is happening.
http://www.youtube.com/watch?v=UuBaoY3fw5o
I have DC power supply powering a bifilar coil at 6V.
Power winding on the coil is drawing, on average, 0.1A.
Tiny rotor with 4 magnets.
Reed switch.
The multimeter is reading up to 100's of volts and tens of amps being output on the secondary winding of the coil.
The strange thing is is that whichever setting i choose to read from on the multimeter the reading is always within that range, ie, if i'm on millivolts then i get, say, 40 mV or if i am on the 200V setting i get 40V ...
Multimeter and PSU are brand new, i have tested them both and they operate normally.
Obviously this is erroneous but why is it happening ?
I have seen this also.
The reason is because inexpensive Chinese digital meters don't have very good shielding to RF. The more RF a circuit outputs, the more erroneous the readings get.
If you use an "old fashioned" analog meter with a needle, you will get more accurate readings.
.
Thanks for that i'll order one.
Hi Folks,
There is another possibility, besides what FatBird wrote.
Try to connect an electrolytic capacitor in parallel with the diode bridge output. (even a 47uF or higher (microFarad) 35 - 63V rated would do)
I suspect all the voltage spikes from the coil go into the meter via the bridge and fool the meter inner circuits. A simple try would be worth it.
EDIT: nevertheless, an analog multimeter is always good to have, besides a DMM, to learn about more truth when tinkering.
Gyula
Deepcut
Great to see another dedicated researcher,I'm glad the fellows that "know"
could offer some assistance.
I hope to see more "anomaly's" from you soon [of the third kind] :o;
Thanks
Chet
Thanks for replies and help :)
I am picking up an old CRT monitor from a hazardous waste place this afternoon and will grab a cap from it.
Will have analogue meter delivered Tuesday.