Recent content by memoguy

Hi there! Just say I have large square piece of some homogeneous resistive material like graphite. How would I go about determining the resistance between any two given points? Further, just say I supply a voltage across two arbitrary points, can I determine the voltage difference between any...

Hi all! Let me use an example to make this clear. There is a car traveling directly toward a man at 10m/s. The car is pressing down its horn, producing a frequency of 100hz. The speed of sound is 330 m/s. What frequency does the man hear? Ok, so we can use the equation: f_observer=(...

Hi! So I know that in electrolytic solutions current is transferred via ions, but I don't understand where the resistance comes from. I know that electrolytic solutions follow ohms law and Pouillet’s Law, but I do not understand what is actually going on that causes resistance. I understand...

Well I have already bought the parts, so I will just make it and see how the distribution is.

Thanks Jim. That is very helpful. I am thinking of making one minor change, that is using one of these http://australia.rs-online.com/web/p/rectifier-schottky-diodes/0230838/ diodes just because they have a slightly slower voltage drop and combine the two diodes. EDIT: I will use this as it...

Ok. I am thinking I will use the LED, diode, switching solution Jim suggested. I can just use a small receiver on a linear regulator for RX. Ok, so I am thinking of getting this: http://australia.rs-online.com/web/p/switching-regulators/6664372/...

Is this only an issue on RX? As we are not really using RX, only TX. Thanks for your tips, if this is going to be an issue of TX then we will have to go for the linear solution you suggest.

Re Jim: Thanks for your response. Ok, I have read about using oring diodes to run switching regulators in parallel. Have you had success with doing this? In relation to the medical grade 1.5A version. I have seen it, however I do not have a easy way to acquire it, the shipping from...

That could work but it is super heavy . This is a high altitude balloon project so weight needs to be low as possible :)

On the whole of RS there are two solutions which fit these criteria: 2A+ 6.5V output possible And they are both $285! http://australia.rs-online.com/web/p/switching-regulators/4459787/

I am sorry - I totally agree. I do want to choose the best option, and if that means paying a substantial amount for it I will. I just find it a bit hard to justify $40 shipping for a single component :) Ok, so that component doesn't seem to be a good match anyway. Looks like I need a 2A reg at...

That is another option. The problem is that I need a black box solution (no external parts), that I can get access to easily & cheaply in Australia. I could say buy this from digikey, but it is almost $40 shipping...

Ok, I am an idiot. I made incorrect measurements. The peak draw is actually ~1.3A to ~1.5 continuous. (I.E. not for a fraction of a second, for all the time I am keying the radio) I am very sorry about that mistake. So it looks like I will have to ask the manufacturer. Thanks for your...

For a high altitude balloon I need to power a radio that draws 1A but briefly peaks at 1.4A for a fraction of a second. <SEE EDIT> I was thinking of using two of these in parallel: http://australia.rs-online.com/web/p/switching-regulators/6727133/ Or one of the above item and one of these in...

I am an idiot. I am so sorry, I see it now!