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1
Projects Q/A / Re: question about PIR
« Last post by audioguru on Today at 10:23:55 AM »
A PIR probably does not have Mosfet pins. Most have an ordinary little transistor at the output that drives an external relay, power transistor or power Mosfet.
If you put a jumper across its two output pins then it will probably stay turned on.
2
Projects Q/A / question about PIR
« Last post by firefli on January 24, 2015, 12:57:58 PM »
I Have a LED light with a motion sensor and photo sensor.
I would like to eliminate the motion part so the light is on all the time when it gets dark.
the QUESTION is would putting a jumper across the source and drain or the source and gate
of the PIR turn it on all the time.

Any advice would be appreciated, Thanx
3
Power Electronics / Re: Variable PSU stability problem
« Last post by tempray on January 23, 2015, 05:17:01 PM »
Everything is connected, facing a new wall, cant connect one of the unit's "+" to the second identical unit "-" side to form dual-polarity PSU(series connection).

Transformer has two secondary windings... interesting that i read 30V on multimeter if probe is connected to the first unit output ground and second unit positive output... seems that they share something...

Any tought's someone ?

EDIT, I found the problem and its good to know if u are about to build PSU.

If you buy an ammeter+voltmeter(dual-led light blue/red display) from e-bay and you plan to buy them 2 for split(series=dual-polarity, symmetrical configuration)  then build also 2 identical power supply's to the ammeters/voltmeters from e-bay. I had ONE 5V power supply for TWO ammeters/voltmeters and i couldn't connect power supply boards in series(short-circuits, lots of firework from output pins) because of ammeters having 1 power supply :D... So i build 2, each 5V, now totally separated.. everything is in place now and working good.

I will photo the work Tommorow for a preview to give u some motivation to build your own:D
4
Theory articles / Re: comparator for DC voltage
« Last post by Hero999 on January 23, 2015, 03:49:10 PM »
It isn't a comparator.

A common ground is needed because all voltages in a circuit are relative to one another. Measuring potential difference is like measuring distance: you need to start from somewhere.
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Electronic Projects Design/Ideas / Re: Mini HD Video Recorder
« Last post by jtroutt19 on January 23, 2015, 09:00:16 AM »
It is a pusher glider. But no I am trying to save space in the canopy for other things eventually. That is why I am wanting to put this together myself. So I can build it to suit my needs.
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Electronic Projects Design/Ideas / Re: Mini HD Video Recorder
« Last post by pebe on January 23, 2015, 05:02:35 AM »
I am surprised that you would get excessive vibration in a glider.
No chance of mounting a camera on a light elastic suspension, I suppose?
7
Theory articles / Re: the finer points of electronics - I
« Last post by KevinIV on January 22, 2015, 10:33:30 PM »
In the quation v = L di/dt.  The voltage goes up and the current goes up. In the equation
i = C dv/dt. The voltage goes up and the current goes up.

8
Electronic Projects Design/Ideas / Re: Mini HD Video Recorder
« Last post by jtroutt19 on January 22, 2015, 08:19:47 PM »
Um no..... To much vibration to provide a clear picture. I will figure something out on my own. Seems like this forum is tapped for collaborative ideas. ???
9
Electronic Projects Design/Ideas / Re: Mini HD Video Recorder
« Last post by pebe on January 22, 2015, 08:28:13 AM »
That link you provided would be great if the after the camera the body bent at a 90 degree angle.
Could you 45degree angle a small mirror in front of the lens?
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Theory articles / Re: comparator for DC voltage
« Last post by pebe on January 22, 2015, 05:27:18 AM »
Where are you going with this discussion? Your posting is not meaningful unless it is aiming for a conclusive point.

So far, I have not seen anything about the subject of the thread, ie. "comparator for DC voltage".
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