Recent content by larny

1. I expect that the shield is used as the antenna. The shield is not connected to ground, therefore it can receive radio signals. 2. The frequency of the RF signals are much higher than the audio range so we can't hear them. Besides, the headphones would not operate at those frequencies...

Here is an even simpler suggestion. Select R1 to give you the output voltage you want. Vo will be approximately 0 Volt when there is no light on the diode.

I just re-read what you want and I realized my previous suggestion was more complex than necessary. My improved suggestion is attached. This will give you flexibilty in choosing the output voltage & voltage range you want.

You could draw a diagram with MS Paint or PowerPoint. Or you could modify one of the drawings that have been posted to show us how your circuit is wired. Otherwise, we are working in the dark.

The gain is set by the resistor values & there will be virtually no DC common mode voltage with the circuit I posted. And the common mode rejection will be quite high provided that the resistors are matched, ie. R1 = R2 & R3 = R4. Use 1% resistors or select on test from several.

A picture is worth 1000 words. See attachment. Use two 9 Volt batteries to give you a + 9V & a -9 V supply. Note that you also need the 100 nF capacitors for stability.

Your post is rather vague. What do you mean by "a difference of 1.x v or 2.x v and if i check the voltages going into the v1 and v2 the difference is only 100mv"? If all of the resistors are equal to each other, then the differential gain will be approximately = 1 as stated in the document...

Have you seen these threads? https://www.physicsforums.com/showthread.php?t=383720 https://www.physicsforums.com/showthread.php?t=314265 https://www.physicsforums.com/showthread.php?t=314265 https://www.physicsforums.com/showthread.php?t=230313...

Thanks again GrayGhost, I'll take your advice & concentrate on the Minkowski approach.

Yes but I'm rusty on it. I studied it some years ago when I had my last burst on SR. I have attached a scan of the title page of the book I have and a scan of my scribbles on a scan of a Minkowski spacetime diagram from page 78 of that book. I need to revise it, but first I want to read...

Thanks agains GrayGhost. I need a day or 2 to think through what you & JesseM have written so far. However, one question. In space, we know that z = ax + by +c is the eq of a plane. Now, Einstein's eq for Tau can be written as Tau = gt + hx' where g & h are functions of c & v...

I suggest that you have 2 power rails, say +15V & -15V. Connect a resistor to each rail (equal resistors) and connect the strain gauge between them. Then connect the ends of the strain gauge to the inputs of a differential amp (use an Op Amp configured as a diff amp). Use capacitors to...

It would help us to help you if you attached a drawing of your circuit. Otherwise we can only guess.

Thanks for the response. As I understand it, the x & X' axes are co-incident. So why does it matter that I have not shown the X' axis? My assumption was that the Tau value at any point Tau (x , t) would be perpendicular to the x, t plane & equal to the distance between the x, t & Tau...

You're welcome. I remembered that the Australian electronics magazine Silicon Chip published a circuit for a "Jacob's Ladder" that uses a car ignition coil as the transformer. So it is essentially what you need. I did not read the article, so I don't know what the output voltage is...