1a. yes, if you have a natural ability or have learned how to study well since being in college
1b. start with calculus, where you have issues in algebra and trig you need to go back and fill in those holes. Do an entire calculus book. Next move on to differential equations and linear...
Ya, using a ferrite bead was just stupid, but I was desperate for a part, and pulled it off a board. I'm going to need to get some big inductor values, and I'm also going to make a preamp with a better drive ability so my AC signal has some balls behind it.
Going with the AC coupling cap and passive circuit ideas:
I built up a circuit and was able to get the AC + DC signal onto the wire with an AC coupling cap. Now, my problem came, as I suspected, when I loaded the combined signal down with a DC load, it completely knocked out the AC signal from...
DC current in that setup would only need to be 20mA at 1.5V at the most, I will probably need to increase the voltage at the other end to drive the LED. Audio signal will be probably ~60Hz to 10kHz, although the higher range I can get, the better. The amplitude will be about 1 to 2 Vpp at...
Hmm, I did this for a GPS active antenna circuit, but the ind and cap values were very small since the frequency was 1.575 gigahertz and at low power. I will probably need large values for audio signals without distorting them.
Thanks for the help, I'll give this a hard look.
Well, ideally, I'd like to touch the AC signal as little as possible, so no opamp would be great for me. I just was always under the impression that its bad to tie two voltage sources together, and that they wouldn't necessarily add together just by shorting them together. I'll run through the...
On second thought, I'm wondering if I can just delete out that audio signal conditioning block all together if I can modify my summing circuit to give me what I want by itself. That way I don't have to worry about the DC load changing because of additional active circuitry.
Alright, attached is sort of what I've been planning to do, and I've simulated it with real opamps, except for the DC power distribution scheme, which is what worries me the most.
Do you think I could make something like that in the size of say a flash thumb drive for each end? The part you suggested looks huge, but this looks like it could be promising.
Also, does everyone think that the OpAmp summer circuit is suitable for forwarding DC power? I didn't say it explicitly, but I can't imagine needing more than 100mA of current at about 1.4V out to the receiving circuit depending on what I do on that end.
Alright,
Luckily the LED current won't saturate a cheap inductor.
Unfortunately, I am dealing with very low frequencies (audio) so my inductive reactance will be low without a large inductor value, and that will take up space and cost.
This is leading up to another important question I...
Hmm this is interesting, and I'd investigate it further, but the design I'm doing has to be low profile and low cost, I'm worried two transformers would take up more space than I can afford. I'll keep this in mind though, thanks!
I just reformatted my PC and don't have any tools on it yet, but I'll install office and make something so you can tell me if I'm on the right track or if I'm making a problem out of nothing.
My problem is that I need to tap into this signal for the DC supply with a resistive load. If I load it down, I will be loading down the AC and it simply won't pass through the capacitor . . Unless you suggest I put an inductor in series before my DC load? I just don't want to dissipate the AC...