Recent content by md5fungi

Wow, these are both very good points. It's a good point that the resistors may behave differently at high frequencies, and possibly have a significant self-inductance. I think we have access to antenna analyzers that will help us make some impedance measurements at HF. It's also a good...

vk6kro, I spiced the circuit using LTSpice and also Multisim. The results were satisfactory. I still, however, cannot measure the power correctly. We've done all sorts of things to measure the power. We're calculating Real Power by using Vmax values and using the equation P = 1/2(Re(VI*))...

Once again, vk6kro, thanks for the information. You have been a huge help. I'm going to try spicing the circuit to see if I get similar results, and hopefully this mutual inductance/coupling coefficient is the missing piece of the puzzle to get our calculations to turn out. Phrak, the...

Didn't quite realize that, but we're using a larger spiral antenna for our receiving coil now. From how we hold the spiral receiver relative to the big loop transmitter, it seems to behave how you'd expect a magnetic field to behave.

It looks like your attachment is broken. Can you reattach it or link me? Also, the 3.00 Mhz frequency is ballpark, I believe it resonates at something more like 2.926 Mhz or something... Regardless, I'm interested in what equations you used to find the voltage across the receiver coil. You...

Vk6kro, thanks for the info. I will read over your post, compare it to what I'm getting and get back to you. Seb7, I will take a look at your links, but a claim of over 100% power efficiency violates the first law of thermodynamics and if such a circuit truly existed I think the entire world...

I realize the power being transmitted has nothing to do with R2; R2 is ONLY USED to measure current. We're not actually measuring the power transmitted, we're measuring the power SUPPLIED by the signal generator. We get the voltage by measuring the voltage across L1, C2, and R2... which is the...

Is there any documentation this? As much documentation as possible would be nice since this is for a senior project, and we need to be using reliable sources.

We are using 3.00 Mhz. The problem is our measurements are incorrect; we ARE getting over 100% efficiency with our measurements, which indicates something is wrong with our measurements. It is critical that we can record accurate measurements of the power transfer in our circuit. Here is the...

Providing an update after one semester of work, and seeing if anyone can find a solution to our problem. Using equations for resonance and inductance, we have managed to light our LED up to a meter away using a big loop antenna transmitter and a spiral antenna receiver. We have also designed...

Hi, I would just like to provide an update of our project. We haven't had a chance to look into all of your suggestions, but the impedance matching on our transmitter made a HUGE difference. The LED lit up at what looks like full brightness. We calculated our power transfer, and seems like...

One last quick question: When I run my program in Linux, it doesn't quit automatically; I have to Ctrl-C out of the program. This is problematic, because I want to use "time ./a.out" to see how long my program runs, and I can only see that result after I push Ctrl-C, thereby giving me an...

Alright; thanks a lot for your help!

So, I have everything correctly implemented, except possibly my processes running concurrently. I got rid of the waitpid function, and it still seems like the order is Process 0, 1, 2, and then 3. Is there something else I need to do to make them run at the same time? Is there an easy way to tell?

Ohh... I figured it out. I'm supposed to increment current_number[i] every time the loop reads the next line... but I was only doing it if it passed the test, which makes no sense.. Aha, I'm an idiot. Thanks for nudging me in the right direction!