Testing the TK Tar Baby

[TinselKoala]

That is indeed truly amazing. Is he really going to be able to just get away with applying the duty cycle twice?
He did actually correct his "divide by three" and went ahead and divided by four, apparently, to get his new figure of something like 4 Watts.

In post #163 he describes his procedure to obtain the figure.

The frequency = 62,500 Hz,
V = 25.3
RL = 10-Ohms
Duty cycle = 25%

1/(4x62,500) = duration of a single pulse = 0.000004 or 4usec
25.3V / 10-Ohms = 2.53A
25.3V x 2.53A = 64.009Watts per pulse
64.009watts x 0.000004sec = 0.000256036Watt-sec per pulse

There are 62,500 pulses per second so:
(0.000256036Watt-sec / pulse) x (62,500pulses / sec) = 16.00225Watts
In the latter calculation, I have essentially added up all of the identical packages of instantaneous power, but they are spaced apart over time.

That is right, and in other words, the duty cycle has already been applied here, since the 4 microsecond ON time is 1/4 of the 16 microsecond PERIOD of a 62.5 kHz oscillation. You have added up 1/4 second's worth of ON times and averaged their power over the whole second. The 16.00225 Watts, artificially precise, is Joules PER SECOND and you have one second's worth .... meaning that the duty cycle of 1/4  has already been factored into this figure.

This is NOT continuous power.  For a 25% Duty Cycle, the FET (switch) is closed or "ON" for 25% of the entire pulse period and is open or "OFF" for the remainder of the pulse period or 75%. 

Now this will shock some: The ratio of "ON" times to "OFF" times is:
.25 / .75 = 1/3 even though the ratio of "ON" time to the entire pulse period is .25 (25% Duty Cycle).  My instincts tell me that I should divide the SUM of the Instantaneous powers by '3'.

So, I will do that:
16.00225Watts / 3 = 5.334083Watts
An RMS calculation will yield similar results.

This step has apparently been "corrected" and now Gmeast divides by 4 here, presumably. Thus he obtains a figure of about 4 Watts here.

But he has already applied the duty cycle once, to get to the 16 Watts figure !! How can he possibly think that it should be applied again?
And it appears in his latest, by using the mean battery voltage and the mean current he is again making the same mistake twice.

Am I wrong in this thinking?

[fuzzytomcat]

That is indeed truly amazing. Is he really going to be able to just get away with applying the duty cycle twice?
He did actually correct his "divide by three" and went ahead and divided by four, apparently, to get his new figure of something like 4 Watts.

In post #163 he describes his procedure to obtain the figure.

The frequency = 62,500 Hz,
V = 25.3
RL = 10-Ohms
Duty cycle = 25%

1/(4x62,500) = duration of a single pulse = 0.000004 or 4usec
25.3V / 10-Ohms = 2.53A
25.3V x 2.53A = 64.009Watts per pulse
64.009watts x 0.000004sec = 0.000256036Watt-sec per pulse

There are 62,500 pulses per second so:
(0.000256036Watt-sec / pulse) x (62,500pulses / sec) = 16.00225Watts
In the latter calculation, I have essentially added up all of the identical packages of instantaneous power, but they are spaced apart over time.

That is right, and in other words, the duty cycle has already been applied here, since the 4 microsecond ON time is 1/4 of the 16 microsecond PERIOD of a 62.5 kHz oscillation. You have added up 1/4 second's worth of ON times and averaged their power over the whole second. The 16.00225 Watts, artificially precise, is Joules PER SECOND and you have one second's worth .... meaning that the duty cycle of 1/4  has already been factored into this figure.

This is NOT continuous power.  For a 25% Duty Cycle, the FET (switch) is closed or "ON" for 25% of the entire pulse period and is open or "OFF" for the remainder of the pulse period or 75%. 

Now this will shock some: The ratio of "ON" times to "OFF" times is:
.25 / .75 = 1/3 even though the ratio of "ON" time to the entire pulse period is .25 (25% Duty Cycle).  My instincts tell me that I should divide the SUM of the Instantaneous powers by '3'.

So, I will do that:
16.00225Watts / 3 = 5.334083Watts
An RMS calculation will yield similar results.

This step has apparently been "corrected" and now Gmeast divides by 4 here, presumably. Thus he obtains a figure of about 4 Watts here.

But he has already applied the duty cycle once, to get to the 16 Watts figure !! How can he possibly think that it should be applied again?
And it appears in his latest, by using the mean battery voltage and the mean current he is again making the same mistake twice.

Am I wrong in this thinking?

Nope ........ but gmeast (greg) gets my FAMED illustrative award for his contribution in "Over Unity" computations ...... need some scissors greg ?

[fuzzytomcat]

Then there's Rosemary Ainslie that needs to "grow up" and learn how to properly test a circuit a new way ....

[WilbyInebriated]

Then theirs Rosemary Ainslie that needs to "grow up" and learn how to properly test a circuit a new way ....

there is...    you really should learn the difference between there, their, they're and there's.

there is a place.  eg: go over there.
their is possesive.  eg: their house is over there.
they're is a contraction of 'they are'.
there's is a contraction of 'there is'.

there. now you are a little smarter. need 'hooked on phonics' fizzy?

[poynt99]

I see Rose has found time between acting as a sock-puppet for someone else's questions on her own forum, and humiliating herself with sock-puppetry of her own on here, to step in and revise history once again.


She's bravely taken the opportunity to delete .99's infinitely courteous and on-topic posts and to paint them as somehow argumentative or abusive. I'd almost feel sorry for Greg being pulled along by the nose, if it wasn't for the fact he's proving to be a total bell end.

I've been banned from Rose's playground. I guess it's a "complete" ban as I am not able to read the forum at all...and it's not set to expire. 

Thanks Rose, I truly mean that.