I believe the sensitivity is very much a function of the geometry of the inductor.
I agree also. I do not know what will increase the sensitivity or distance at which the circuit will pick up the EMF. Ideas?
I believe the sensitivity is very much a function of the geometry of the inductor.
I looked up the stormwise one, seems really promising, but if I were to use one of those 2000u rods, won't that throw off the whole circuit? I mean the basis of the design was around the inductor isn't it?I am not an expert on antennas.
You could try a big loop, or a coil wound on a ferrite rod. Have a look at
http://www.radio-electronics.com/info/antennas/ferrite_rod_antenna/ferrite_rod_antenna.php
http://www.stormwise.com/page26.htm
Google "ferrite rod". Some of the crystal radio parts suppliers sell ferrite rods.
Interesting, is there a graph that plots out the inductance vs. sensitivity on that sim? Is is possible to post it?According to simulation, raising the inductance lowers both corner frequencies and raises the sensitivity.
Yes I found this while testing it around the house. It works best at right angles to the source.In any case, your sensitivity will probably be directional, so rotating the antenna might pick up one source and lose another one.
OK, here is the results of the sim, using 1mH and 10mH. No guarantees. I don't even know if I modeled the inductor stimulus correctly.Interesting, is there a graph that plots out the inductance vs. sensitivity on that sim? Is is possible to post it?
Yes I found this while testing it around the house. It works best at right angles to the source.
OK, here is the results of the sim, using 1mH and 10mH. No guarantees. I don't even know if I modeled the inductor stimulus correctly.
TL084 should be fine.Thank you Ron H, it looks like that the 10mH inductor gives you a good gain increase throughout the entire bandwidth, up until the higher end of the frequencies. I did notice that you modeled the TL074 though. Will this matter in real life testing that I have the TL084?
I checked it. It appears to be electrically correct, except you will have to mount the transistor on the bottom side of the board, according to the datasheet. The picture there is of the top side of the transistor.BUMP
Is no one able to give input on the circuit layout?
I could really use the help on this.
Thanks in advance, to anyone who is willing to help on this.
I checked it. It appears to be electrically correct, except you will have to mount the transistor on the bottom side of the board, according to the datasheet. The picture there is of the top side of the transistor.
I don't like the length of your ground trace, but it would be difficult to fix it on a single-sided board. Of particular concern is the length of the path from pin 4, through C5, to pin 11. It needs to be much shorter. If the circuit oscillates, connect another 100nF cap from pin 4 to pin 11 on the back side of the board, using very short leads.[/QUOTE]
Thank you Rom H, I can see that the V- lead is too long, I will try to shorten it without sacrificing the layout, as well as fix the Q1 orientation!
The V+ through R10 to pin 4 then throuh C5 can be shortened, I will try to fix that tomorrow along with the rest. - Will this be the major cause of oscillation? If I were to fix another 100nF cap on pins 4 & 11, it will be very hard for me to do so on the back side of the board, I do not have the proper drillset up to make the .82mm hole size without breaking the bit!
Thank you for the professional input! I will make the changes and post the result.
Your original layout had a shorter path length from pin 4, through C5, to pin 11. I have highlighted it in red on the old layout and the new one. I didn't check the rest of your new layout.
Are you aware that the 4 op amps on the chip are interchangeable? You don't have to use the pinouts that I showed on my schematic. If rearranging them can shorten the traces and make the layout simpler, then do it.[/QUOTE]
You know that is something I didn't even think of!
I will see what I can come up with on Monday, I do not have the pcb file with me at this moment. Back to the drawing.... um, monitor?
I see about the ground trace between the old and new layouts, I will try the amp switching and see what comes of it.
Again Ron H, you have givin me great insight! Thank you again!
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