Resistance of ammeter caused voltage drop

current?- and you don't even have the sign right.

worthless p.o.s.- we are wise to your dumb ass-

What a simple-minded little fairy and brainless pussy you are- the OP already said that he gets 1.85A at 7.0V without the ammeter- so who needs your crap and pretentious pseudo- engineering formula? You want to assume linearity for voltage drops less than 10%, then that there tells you the effective power supply output resistance is 0.5V/1.85A=0.27 ohms. Then because the OP also states the load voltage is 6.14V at 1.80 with the ammeter, you have that 7.5V=1.8*0.27+1.8*Rammeter+6.14V or Rammeter=0.486 ohms. The OP also states that without transmitting, the drop due to the ammeter is 0.3V making I= 0.3V/(0.486+0.27)ohm=0.4 amps at 7.2V load voltage- or a load power of 7.2*0.4=2.9 Watts. The load power during transmit w/o ammeter is 7*1.85=13W and the load power w/ ammeter is 6.14*1.8=11W. The ammeter deprives the circuit of 2W of load power,- so that the RF output will fall something like eta*2W where eta is the transmit efficiency. Say for example eta is 33% more or less over these power consumption ranges- then he must lose about 0.7W transmit power- if he has a lot of Class A overhead stuff then eta may only be

Everything you say is worthless trash- and is to be disregarded- you don't know what you're doing- you are an engineer impersonator and a sociopathic narcissist. GFOAD.

You will be gone soon- it is easy to shoot down every one of your posts- you are so ignorant and prone to error. Your posts appear to be an excuse to tell us more about your life experiences, every one of which seems to be some sort of gloating about exposing someone as vastly inferior to yourself- you are a true reject, and of no value to USENET. You can score your "contribution" to this thread as yet another zero- totally worthless verbiage- mainly because you failed to comprehend the question- this inability to understand what others have to say is another symptom of your narcissism- you don't care what they are saying- they are not in your tightly sealed internal universe. You are a very sick reject.

....

I figured if he had a variable supply, he would not be so concerned about voltage drop. I tend to assume, until shown otherwise, that people have a modicum of intelligence and initiative. So it would not occur to me to ask if he thought of turning his supply up, although I gave him a subtle hint that such might be possible.

As for the OP's possible possession of a supply with remote sensing, I tried to concentrate on what he claimed to have and give him a workable method within that constraint. A long list of questions about what else he might have did not seem time effective for him or me. I spent a short time considering what supply he had and decided it was likely something simple, probably hobbiest grade, since he could not trust its current meter. Then I decided not to worry about it and take its output as fixed.

If you want to label those judgements as "ignorance", "lack of familiarity", "rush to judgement", or anything else from your panoply, be my guest and I hope you get as much out of it as I do.

In context, my "knew of" clearly refers to my knowledge or alleged lack thereof. This last point is getting to be a real sidetrack.

That's right, for reasons stated.

HaHa. What makes you so sure he had a variable supply? And that it could be set higher than he had already set it? The guy comes here wondering what to do about a few 100mV of supply drop, knows enough electronics to recognize some issues that concern him, and I should start asking him if he has thought about doing the most obvious things that anybody with the sense he already exhibits would not need to come here for? LOL indeed! Thanks, but no thanks. I'll leave the insulting in the capable hands of you, Fred, and all your invisible friends.

Ok, I'll bite. (But I must say, your stupidity guage has some strange attributes given our recent chat! ;^) Be sure you do not let any lack of imagination affect your notion of how stupid that idea actually is.

That may well be true for your stuff. It just goes to show that your experience, or anybody's, is limited and does not constrain reality. Maybe, since those resistors (when they exist) are inside the supply, you just never noticed them.

....

"Chicanery" is a little much, John. Nobody was hurt or even sorry it happened. I am sorry that this is not obvious to you, and that you have to leap to that kind of unwarranted conclusion.

I should caw here about how few seconds that would take to find on your own, (assuming you could remember how to spell my name for a few moments), but seeing as how you've been such a helper with Google: US 4656416

Oh Woe Is ME! I only have three. (For three phase EC motors :-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

Mine are 50A FS.

...Jim Thompson

Ouch! You guys sure know how to pile on. That's very close to the most damaging blow so far.

Thanks, and likewise.

Congratulations. You hit the dumb-ass trifecta.

yeah, those gold buckles on your shoes look a little out of style.

Was he getting paid by the hour? ;-)

Cheers! Rich

Clearly its pick-on-Larry O'clock, so here's my 2 cents worth:

I dont like your hat

Cheers Terry

Why not stick one of the power supply leads thru the centre of a DCCT (aka hall effect DC current transducer). Surely everyone has half-a-dozen of these sitting in their junk box?

Cheers Terry

Bad Jim! :{

Alas, all 12 I have are 300A rated, 3x overload.....

I must buy a few smaller ones :)

Cheers Terry

What can I say, I'm one of the people my parents warned me about :)

wrt OP, I once had the brilliant idea of incorporating -ve feedback into a TL431-opto feedback circuit, by placing the LED resistor at the o/p rail, then taking the o/p voltage feedback from the bottom of that resistor in order to reduce the maximum gain and stabilise it (Aol is all over the show for a TL431). OK, fair enough, it ought to work. In order to test it, I slapped a Fluke87 (in mA mode) in series with the TL431. The voltage drop across the ammeter was more than enough to screw up the entire circuit (esp. since it was in the -ve feedback part), and as I was being particularly thick that day it took several hours for me to figure out why it didnt work.

Thats not so bad. What really hurt was my tech roaring with laughter when he found out what I had done, then calling the other guys down for a laugh. Perhaps it was revenge for the time I kicked him in the ankle whilst his head was under a shelf - ouch clonk f*ck OWTTE ;]

Actually it was probably payback for the time I gave him a dish containing about 10,000 0603 caps (200 values), and asked him to sort them out. Half an hour later, there he was painstakingly measuring each one, until one of the other techs took pity on him and told him the correct response to such a request was "piss off"

Cheers Terry