A Solid State DC-to-DC converter

[teslonian]

Not sure what to make of this. The guy clearly shows everything in plain view.

https://youtu.be/_gIuB-f-VnU

[Dog-One]

Why in God's name does he have the two positives of the DC2DC converter connected
together when the negatives are already connected together?

If someone would like to spend a moment drawing a schematic of this guy's rats nest
of wires, I think you will see pretty quickly the error of his ways.

[teslonian]

Why I don't know, perhaps you should ask the guy yourself. He mentions in the video that the negatives of both the input and output are already connected internally and so there is no need for an extra negative connection.


It appears that he has then connected the output positive to the input positive in order to create a feed back loop within the circuit in an attempt to charge the DC power supply he's got there which appears to be a mains wall adapter of what looks like 12V.


The meter is in between the positive output and the positive input to show power going back to the source. Looks simple enough.

[e2matrix]

That's a common dc-dc converter you can buy that exact one off eBay for less than $5.00 which includes shipping.  Bought one as I have several and use them for a variety of things.   Will test but not sure the test shown is valid.

[gyulasun]

Hi Folks,

I copied and edited a schematic of the step up DC/DC converter shown in the video, here is the data sheet:
http://www.ti.com/lit/ds/symlink/lm2587.pdf  and I attached the drawing below. I believe the full set up youtuber 'debunkified' showed in his video is correctly represented in my attached schematic.

In the schematic I indicated the two Ampermeters he used in the negative rail of the step up converter and the one used in the loop back wire between the positive input and positive output.  I wrote the voltage levels at the input and at the output he measured with digital voltmeters when the two currents were also measured but I did not use voltmeter symbols.

Here are some of my comments I included also to the Comment section under the video:

Practically the "output" power may be considered  as follows: the voltage difference between the output-input of the step up converter is 12.31V-12.28V= 0.03V so the power dissipated mainly in the inner circuit (15uH coil and the diode) and in the inner resistance of the Ampermeter is approximately 0.03V*0.692A=0.02W

Notice that this dissipated power is higher for the analog Ampermeter case where he measured the data at the end of the video as follows: Vin=12.28V  Vout=12.51V   Iin=19.2mA   Iout=200mA so the dissipation is 0.23V*0.2A=0.046W 

It seems to me from these measured data that the inner resistance of the Ampermeter in the loop back circuit mainly determines the current, together with the amplitude level of the adjustable output voltage of course. (the used Analog ammeter may have slightly higher inner resistance in the 250mA range than the used digital meter in the mA range).

And he probably experienced a narrow range within which the so called "output" current is higher than the input current into the negative rail of the step up converter. Suppose he would use, say, a 10 Ohm or 22 Ohm resistor in series with the "output" Ampermeter, and say he would set 0.5 to 1V input-output voltage difference, then the overall dissipation in this resistor would probably be higher than that of the inner circuit dissipation I referred to earlier. I am just trying to take out real output power with this pondering. Question is how the input current to the negative rail of the converter would change then.

My overall conclusion is that this circuit does not produce extra output versus the input, unfortunately. I say this as per my personal impression by analyzing the circuit and the measured and presented data on it.

Gyula