Search found 17 matches

by sparkle
Tue Mar 25, 2008 8:46 am
Forum: General Discussion
Topic: Playing with disposable flash...
Replies: 12
Views: 1826

Yet another xenon reference design:
http://www.zetex.com/3.0/appnotes/design/dn31.pdf
by sparkle
Wed Feb 20, 2008 5:13 pm
Forum: General Discussion
Topic: Experimenter Board Help
Replies: 16
Views: 4069

...The solution adopted by many switch companies is to construct wiping contacts that provide self-cleaning without the need for deliberate contact arcing... And the relatively good performance of modern debounced keyboards worldwide (at least up to the first massive coffee or toner spill) shows ho...
by sparkle
Wed Feb 20, 2008 2:44 pm
Forum: General Discussion
Topic: Experimenter Board Help
Replies: 16
Views: 4069

...I still occassionally get a phantom dim output light. But it is sufficiently different from an 'on' that I can explain it to my students... One more consideration is the quality of the switch contacts themselves, a separate issue from bounce. Depending on the construction, environmental contamin...
by sparkle
Mon Feb 18, 2008 8:52 pm
Forum: General Discussion
Topic: A problem for the spice boys
Replies: 25
Views: 5014

I think your LO drive is set very well the way you did it. I think it is delivering the right voltage for an ideal load, the mixer LO port is reflecting some of it, and the sum of the reflected voltage and the incident voltage happens to yield an elevated sum voltage to be measured. But my hunch is ...
by sparkle
Mon Feb 18, 2008 5:30 pm
Forum: General Discussion
Topic: A problem for the spice boys
Replies: 25
Views: 5014

Hmmm, some experimentation may be needed to determine whether the attenuation should be increased to isolate the filter from the oscillator, or alternatively to drive the filter somewhat hard and leave surplus power to be eaten by an isolation pad attenuator to isolate the filter from the nonlinear ...
by sparkle
Sun Feb 17, 2008 9:05 pm
Forum: General Discussion
Topic: A problem for the spice boys
Replies: 25
Views: 5014

... The port I am feeding on this mixer wants to be terminated in 50 ohms. Up to this point, I have not been injecting any LO power which is planned for +7DBM. Do you think the lack of that would affect the input 'Z' at the RF port (the one I am currently having a problem with)? My guess: Looking a...
by sparkle
Sun Feb 17, 2008 4:03 pm
Forum: General Discussion
Topic: A problem for the spice boys
Replies: 25
Views: 5014

...And lastly a high quality scope's true 50 ohm vertical input port. This is the one I use presently. In order to get a true picture of this circuits out put (or any 50 ohm load), I disconnect the circuit at that point and substitute the scopes internal load in place of it as I have done with this...
by sparkle
Fri Feb 15, 2008 11:30 pm
Forum: General Discussion
Topic: A problem for the spice boys
Replies: 25
Views: 5014

Checking matching network design tables confirms your nominal values for the 100 ohm inductive and capacitive reactances to do the 200:50 ohm transformation for your topology but with a Q of 2. I agree that the inductance associated with lead lengths of discrete capacitors partly cancels their capac...
by sparkle
Fri Feb 08, 2008 2:21 pm
Forum: General Discussion
Topic: Relay connection nomenclature
Replies: 8
Views: 1801

Re: Relay connection nomenclature

Dean Huster wrote:Industrial relays, in addition to pin numbers, also have function designations for their terminals... I need something "official"...
Dean
http://www.labplan.ufsc.br/congressos/T ... 06_398.pdf
by sparkle
Fri Feb 08, 2008 11:38 am
Forum: General Discussion
Topic: Relay connection nomenclature
Replies: 8
Views: 1801

Hi. And automotive relays/circuit nodes have a distinctive numbering, like the 85, 87, 88, 30, 15 on post #2 here: http://www.mp3car.com/vbulletin/hardware-development/30019-schematics-pin-outs-diagrams-2.html Which I have never been able to find information about. Does anyone know? Miguel DIN stan...
by sparkle
Sun Jan 13, 2008 12:42 pm
Forum: General Discussion
Topic: Ambitious cheap GPR ideas, not even a pre-project....
Replies: 3
Views: 1166

Re: Ambitious cheap GPR ideas, not even a pre-project....

... the whole contraption towed on a 'radioflyer' cart.... See page 3 of http://www.g-p-r.com/UWB99.PDF :grin: There are many patents and publications on this subject, but US patent 3,806,795 is a good starting point. Transient waveforms have their advantages, but it is possible to probe with a con...
by sparkle
Sun Nov 25, 2007 3:50 pm
Forum: General Discussion
Topic: simple RS-232 data logger
Replies: 13
Views: 3437

The DB-9 female RS-232 interface from a Palm Hotsync cable to a PC is of the Data Set variety (like that of a modem as opposed to a Data Terminal), as is the DB-9 female RS-232 interface from the Garmin eTrek PC interface cable. Now, it may be that the Handspring Visor PDA rear connector requires si...
by sparkle
Mon Oct 29, 2007 12:00 pm
Forum: General Discussion
Topic: Water Boil Detector
Replies: 55
Views: 9283

...sparkle: i am thinking that my first attempt will be with a humidity sensor, but im not sure if i want to go to a high voltage scheme. I'd like to stick with low voltage if possible, like 12v (ac or dc) or less... My megohmmeter can apply from 1 to 999VDC, I had it cranked all the way up to swee...
by sparkle
Mon Oct 29, 2007 10:33 am
Forum: General Discussion
Topic: Water Boil Detector
Replies: 55
Views: 9283

...Have to ask- why a clean new $20 bill?... :grin: Although I had heard some other contributed ideas boiling with potential, I was hot to try to throwing money at the problem. Since my VCR works, I was a little reluctant to disassemble it for testing with the humidity sensor! Clean ATM currrency s...
by sparkle
Sun Oct 28, 2007 8:49 pm
Forum: General Discussion
Topic: Water Boil Detector
Replies: 55
Views: 9283

As an experiment I rigged a paper humidity detector at the vent fan rear exit of my 0.6 Cu ft. microwave oven, which both vents the oven chamber and the outer shell area containing the timer/power supply/magnetron stuff. A better location would be just outside the oven chamber vent holes to sense th...