0:00:05.150,0:00:09.255
>> Here we go. I'm going to use the edge of this.

0:00:09.255,0:00:13.650
I'm already wearing protective glasses because this will cause a big spark.

0:00:13.650,0:00:15.405
Please don't try this at home.

0:00:15.405,0:00:18.585
There we go. I'm going to connect it to terminals together.

0:00:18.585,0:00:22.455
Ready? Here we go.

0:00:22.455,0:00:24.930
I had my eyes closed. So I hope you guys saw that.

0:00:24.930,0:00:27.930
That was the entire charge

0:00:27.930,0:00:30.570
in a capacitor going through the short-circuit tip of this.

0:00:30.570,0:00:36.780
You can see it actually damaged the tip of my X-Acto knife here.

0:00:36.780,0:00:39.265
They wouldn't focus on this very well.

0:00:39.265,0:00:41.570
But now you can see that a voltage across

0:00:41.570,0:00:44.795
the capacitor went down all the way to 11 minus seven volts.

0:00:44.795,0:00:48.890
So, let's now do the same thing, but this time,

0:00:48.890,0:00:53.495
let's take this to the oscilloscope and connect the probe on

0:00:53.495,0:00:55.520
the voltage that I was telling you about, and

0:00:55.520,0:00:59.340
the node I was telling you about I'm interested in seeing.

0:01:00.340,0:01:04.265
I'm interested in looking at this voltage right here

0:01:04.265,0:01:08.490
and seeing the oscillation I was telling you about. So, let's take a look at that.

0:01:09.600,0:01:12.650
Okay. Here we are at the oscilloscope.

0:01:12.650,0:01:14.840
I'm going to be using my older scope for

0:01:14.840,0:01:18.290
this because I'm going to be putting a very large voltage,

0:01:18.290,0:01:21.380
and then I don't want to risk damaging my new digital scope.

0:01:21.380,0:01:25.640
You can buy one of these older CRT-based scope from eBay for about $200.

0:01:25.640,0:01:28.085
They're very useful. I highly recommend it.

0:01:28.085,0:01:30.560
So, here's the flash circuit.

0:01:30.560,0:01:35.420
It's already powered up using my power supply on the left.

0:01:35.420,0:01:38.550
I'm not running this at its full capacity.

0:01:38.550,0:01:42.800
I'm running it only from 0.6 volts because I don't want to create a very large voltage.

0:01:42.800,0:01:45.170
I just want to demonstrate the principle of operation.

0:01:45.170,0:01:49.640
So, what I'm going to do is I'm going to use the oscilloscope probe

0:01:49.640,0:01:54.410
and look at the voltage right before and after the diode.

0:01:54.410,0:01:57.630
So, let me see if I can get this to focus.

0:01:58.600,0:02:01.700
There we go, almost.

0:02:01.700,0:02:04.950
Right. So, here you can see the diode right there,

0:02:04.950,0:02:08.449
and I'm going to look at the voltage before and after the diode so we

0:02:08.449,0:02:12.845
can see the peak detection and also the large voltage swing I was telling you about.

0:02:12.845,0:02:16.370
So, what I'm going to do is I'm going to connect

0:02:16.370,0:02:18.620
the negative terminal of

0:02:18.620,0:02:22.340
my 10 to one probe and it's important that this is a 10 to one probe.

0:02:22.340,0:02:26.930
So, I will connect that to the negative voltage of the power supply.

0:02:26.930,0:02:28.765
I will take this cap off,

0:02:28.765,0:02:30.720
and then we will focus,

0:02:30.720,0:02:33.930
zoom in a little bit more on the display.

0:02:35.230,0:02:40.090
So, you can see the display of the scope is set to 50 volts per division,

0:02:40.090,0:02:44.785
meaning each of these vertical lines and vertical divisions is 50 volts.

0:02:44.785,0:02:47.130
So, there's eight of them in total, one,

0:02:47.130,0:02:49.380
two, three, four, five, six, seven, eight.

0:02:49.380,0:02:53.910
So 400 volts, a peak-to-peak signal can fit in this display.

0:02:53.910,0:02:56.600
Right now, the middle line is the ground.

0:02:56.600,0:02:59.210
So the signal in the middle is zero volts.

0:02:59.210,0:03:05.180
So, I will connect it right where I was saying right before the diode,

0:03:05.180,0:03:07.580
but I'm going to have to do that from the opposite side of

0:03:07.580,0:03:11.040
the PCB because I cannot really reach that.

0:03:11.040,0:03:13.270
I flip it over.

0:03:13.460,0:03:17.070
This is after the diode,

0:03:17.070,0:03:18.900
and this is before the diode.

0:03:18.900,0:03:22.535
I'll put this on the ground and then I will connect it.

0:03:22.535,0:03:26.955
Here we go, like that.

0:03:26.955,0:03:32.180
So, you can see there is an excess of 400 volts peak-to-peak of swing there.

0:03:32.180,0:03:34.790
The negative swing is clipped at the bottom.

0:03:34.790,0:03:36.725
You can see the bottom part is clipped.

0:03:36.725,0:03:41.180
The reason is because that's where the diode starts conducting and,

0:03:41.180,0:03:43.220
therefore, the capacitor starts to charge.

0:03:43.220,0:03:45.320
So, that voltage does not go below there because

0:03:45.320,0:03:48.485
the capacitor is so big that clips a voltage at the bottom.

0:03:48.485,0:03:50.530
But you can see that right now,

0:03:50.530,0:03:53.160
the voltage across the capacitor,

0:03:53.160,0:03:58.535
you can tell by where the clipping happens must be around minus 200, minus 250 volts.

0:03:58.535,0:04:01.730
If I connect this right to the capacitor,

0:04:01.730,0:04:05.875
you can see that it goes below the vertical division,

0:04:05.875,0:04:10.850
below the lowest point here is because it's less than minus 200 volts.

0:04:10.850,0:04:14.450
So, there's one other thing we can get from this.

0:04:14.450,0:04:17.945
If I connect it, we can measure the frequency of oscillation.

0:04:17.945,0:04:21.370
Each horizontal division is 50 microseconds.

0:04:21.370,0:04:23.100
So, if I connect it,

0:04:23.100,0:04:28.415
we can see that the cycle repeats once every 100 microsecond.

0:04:28.415,0:04:30.470
That's equal to 10 kilohertz.

0:04:30.470,0:04:33.830
Ten kilohertz is audible because you can hear 10 kilohertz.

0:04:33.830,0:04:38.670
In fact, you must have realized whenever you turn one of these things on,

0:04:38.670,0:04:42.005
then it makes that really annoying high-frequency pitch.

0:04:42.005,0:04:44.330
The reason that happens is because the frequency

0:04:44.330,0:04:46.760
of oscillation is within the audible range,

0:04:46.760,0:04:49.940
and the coil is in the transformer vibrate ever so

0:04:49.940,0:04:53.780
slightly because of so much cranes in them in the magnetic field.

0:04:53.780,0:04:57.710
Shift them left and right very little just enough so that you can hear.

0:04:57.710,0:05:02.000
So, the whole circuit emits sound when it's operating.

0:05:02.000,0:05:04.475
That's another reason why it makes that noise.

0:05:04.475,0:05:06.650
So, what I'm going to do now is that now we

0:05:06.650,0:05:09.680
have spoken a lot about how this circuit works,

0:05:09.680,0:05:12.020
looked at some other voltage or the oscillation and

0:05:12.020,0:05:14.495
a whole bunch of other characteristics,

0:05:14.495,0:05:17.840
what I'm going to do now, is I'm going to connect this to

0:05:17.840,0:05:22.415
a Nixie tube and then see if we can power a Nixie tube with one of these things.

0:05:22.415,0:05:26.580
So, let's move back to the other side and let's try to do that.

0:05:26.930,0:05:29.775
So here, I have a Nixie tube.

0:05:29.775,0:05:35.825
This Nixie tube shows numbers between zero to nine and it has also two decimal points.

0:05:35.825,0:05:40.130
So, the way these Nixie tubes work is that the gas inside

0:05:40.130,0:05:45.320
this tube is low pressure neon sometimes mixed with mercury and argon.

0:05:45.320,0:05:48.110
You have around on the outside,

0:05:48.110,0:05:49.490
you may be able to see it,

0:05:49.490,0:05:53.040
there's this mesh that's connected all the way around,

0:05:53.040,0:05:56.480
and at the back is a solid plating that's connected to one of these pens.

0:05:56.480,0:05:58.430
That's the anode pen.

0:05:58.430,0:06:02.810
What ends up happening is by putting a large potential difference

0:06:02.810,0:06:05.400
between this mesh on the outside and

0:06:05.400,0:06:08.270
the little numbers in the inside that you may be able to see,

0:06:08.270,0:06:11.300
you're going to excite the neon gas that's in there,

0:06:11.300,0:06:13.705
and the neon gas is going to glow.

0:06:13.705,0:06:16.190
The exact principle of operation of how it

0:06:16.190,0:06:19.670
happens and the physics that goes into it is an interesting read.

0:06:19.670,0:06:21.650
I suggest that you take a look at it,

0:06:21.650,0:06:23.900
but the principle of operation is what I said.

0:06:23.900,0:06:25.265
The gas gets excited,

0:06:25.265,0:06:27.220
the electrons move to higher energy bands.

0:06:27.220,0:06:29.030
On their way back down,

0:06:29.030,0:06:34.570
they emit light in the frequency and the wavelength that we are able to see.

0:06:34.570,0:06:41.595
That happens near the cathode elements of this Nixie tube.

0:06:41.595,0:06:43.695
Why does it happen near the cathode element?

0:06:43.695,0:06:45.800
Now, it is a little bit of physics that goes in there too.

0:06:45.800,0:06:47.775
I recommended you, take a look at it.

0:06:47.775,0:06:50.150
But in order to turn one of these things on,

0:06:50.150,0:06:53.675
you need to apply somewhere between 150,

0:06:53.675,0:06:59.755
160 of volts between the anode and the cathode of this particular model,

0:06:59.755,0:07:01.855
and then you'd be able to turn those numbers on.

0:07:01.855,0:07:04.890
These guys were invented and used back in the '40s and

0:07:04.890,0:07:08.030
the '50s when seven-segment displays,

0:07:08.030,0:07:11.800
an LCD displays and vacuum fluorescent displays weren't available yet,

0:07:11.800,0:07:13.850
and you could show numbers with these.

0:07:13.850,0:07:19.515
So, if you ever had an old HB or a very old measurement equipment,

0:07:19.515,0:07:24.685
you will be able to find these Nixie tubes used as a display, very, very popular.

0:07:24.685,0:07:29.505
A lot of people build very cool things with these like clocks or some

0:07:29.505,0:07:33.575
display depending on what kind of Nixie tube we can get a hold of.

0:07:33.575,0:07:37.145
I got a batch of 10 of them from eBay a while back.

0:07:37.145,0:07:39.410
I can't remember maybe about $50 or so.

0:07:39.410,0:07:41.740
Very cool things to play with but of course because they

0:07:41.740,0:07:44.375
need 150 volts or so to turn them on,

0:07:44.375,0:07:46.510
they are not the easiest things to use.

0:07:46.510,0:07:48.725
So, you will need a DC-DC converter.

0:07:48.725,0:07:49.960
So, I thought why not,

0:07:49.960,0:07:53.095
let's try and power one of these things using a flash circuit

0:07:53.095,0:07:56.810
because the flash circuit is capable of giving us that kind of voltages.

0:07:56.810,0:07:59.665
So, what I've done is that I've taken one of these guys,

0:07:59.665,0:08:03.605
and I have just placed that on

0:08:03.605,0:08:07.755
top of one of these breadboards so that all the legs are nicely separated.

0:08:07.755,0:08:10.640
There is a little resistors connected to the anode.

0:08:10.640,0:08:13.770
So, this wire right here is going to connect

0:08:13.770,0:08:17.050
to the anode and every one of the other wires,

0:08:17.050,0:08:19.935
the cathodes are going to be connected to

0:08:19.935,0:08:24.620
the potential that will turn it on and you should be able to see those numbers.

0:08:24.620,0:08:27.015
So, I'm going to connect everything up,

0:08:27.015,0:08:29.795
show you how it's connected, and then let's see if we can power it on.

0:08:29.795,0:08:32.015
Then, the last thing,

0:08:32.015,0:08:34.360
we're going to measure the efficiency of

0:08:34.360,0:08:38.155
the DC-DC converter based on how much power is delivered to the Nixie tube,

0:08:38.155,0:08:42.065
and how much power is required for the flash circuit to run.

0:08:42.065,0:08:43.625
So, let's do that.

0:08:43.625,0:08:45.600
So, let's see what I've done here.

0:08:45.600,0:08:51.195
I have connected the flash circuit to the power supply,

0:08:51.195,0:08:52.915
so it's powered on.

0:08:52.915,0:08:55.930
I'm monitoring the voltage of the capacitor

0:08:55.930,0:08:59.170
simultaneously like I was doing before on the multimeter.

0:08:59.170,0:09:04.715
I am connecting the anode to ground and I'm connecting one of

0:09:04.715,0:09:10.310
the cathodes to the negative terminal of the capacitor.

0:09:10.310,0:09:12.695
This is because, remember this produces

0:09:12.695,0:09:16.050
negative voltages with respect to the ground of the power supply.

0:09:16.050,0:09:17.915
So, at the same time,

0:09:17.915,0:09:24.895
I am measuring the voltage that is connected to the flash,

0:09:24.895,0:09:28.290
the current that's connected to this that it is being provided to the flash,

0:09:28.290,0:09:30.305
the voltage across the capacitor,

0:09:30.305,0:09:34.790
and the current that is given to the Nixie tube.

0:09:34.790,0:09:39.200
So, if I were to multiply this current by this voltage,

0:09:39.200,0:09:42.295
that's the power delivered to the Nixie tube.

0:09:42.295,0:09:45.455
If I were to multiply this number with this number,

0:09:45.455,0:09:48.090
that's the power delivered to the flash unit.

0:09:48.090,0:09:50.910
So, by dividing the result of this to this,

0:09:50.910,0:09:54.200
I can get the efficiency of the DC-DC converter afterwards.

0:09:54.200,0:09:58.685
But let's first turn on the Nixie tube and see what happens.

0:09:58.685,0:10:07.140
So, let me go all the way down and we bring the Nixie tube into view, like so.

0:10:07.140,0:10:10.750
I'm going to increase the voltage in the power supply until this guy turns

0:10:10.750,0:10:16.730
on. Here we go.

0:10:16.940,0:10:21.785
There we go. Here it is and it's showing the number eight.

0:10:21.785,0:10:27.390
I can show other numbers by connecting it to the other numbers.

0:10:27.390,0:10:31.835
For example, here's number two, three, four,

0:10:31.835,0:10:35.410
five, six, seven, eight,

0:10:35.410,0:10:37.505
and the back that's nine.

0:10:37.505,0:10:40.805
You can also turn one and other ones but I don't want to reach the back,

0:10:40.805,0:10:44.020
all the way back just in case I will short-circuit the wires.

0:10:44.020,0:10:45.845
So, let's connect it back to number eight.

0:10:45.845,0:10:49.380
So, the thing that makes this Nixie tube is really

0:10:49.380,0:10:53.810
cool is the fact that the numbers are not all on the same plane.

0:10:53.810,0:10:56.495
So, it gives it this weird 3D look.

0:10:56.495,0:10:58.075
As I go across the numbers,

0:10:58.075,0:11:00.310
the numbers go back and forth and I think that's

0:11:00.310,0:11:06.065
a really cool retro look and you could incorporate in one of your future projects.

0:11:06.065,0:11:08.360
So, you can see when we're a bit closer,

0:11:08.360,0:11:10.040
the number eight is glowing.

0:11:10.040,0:11:13.130
Very nicely, it has a very nice orange glow color to it.

0:11:13.130,0:11:15.070
So, I'm going to put this down on the ground,

0:11:15.070,0:11:19.795
leave this number eight on so we can measure now the efficiency of the DC-DC converter.

0:11:19.795,0:11:22.645
So, let's put this back down here.

0:11:22.645,0:11:31.880
While it's on, let's go up and look at these numbers. Here we go.

0:11:31.880,0:11:40.975
So, the power supply is set to 0.8 volts and is drawing 386 milliamps.

0:11:40.975,0:11:44.670
So, let's say for the sake of to make it easy in the calculation,

0:11:44.670,0:11:46.355
let's say this was 400 milliamps.

0:11:46.355,0:11:50.240
So, that will be 0.32 watts.

0:11:50.240,0:11:56.120
320 milliwatts of power is being delivered to the flash DC-DC converter.

0:11:56.120,0:12:02.745
The voltage across the capacitor is 133 volts, negative 133 volts.

0:12:02.745,0:12:07.030
The current going to the Nixie tube is 1.2 milliamps.

0:12:07.030,0:12:14.754
So, if you multiply 1.2 milliamps by a 133 and divide that by about 320 milliwatts,

0:12:14.754,0:12:17.295
you get just over 50 percent.

0:12:17.295,0:12:22.900
So, the efficiency, the DC-DC converter efficiency for turning one of these Nixie tube

0:12:22.900,0:12:28.650
on using a flash from a disposal flash camera is only about 50 percent,

0:12:28.650,0:12:31.805
which is very bad because you can make

0:12:31.805,0:12:36.475
DC-DC converters that are easily more efficient than 80 percent.

0:12:36.475,0:12:39.965
But, for hacking purposes and for something

0:12:39.965,0:12:44.260
that would have otherwise been thrown out and for educational purposes,

0:12:44.260,0:12:46.380
I think this is a great project that

0:12:46.380,0:12:48.890
if you have some experience dealing with high voltages,

0:12:48.890,0:12:51.770
I strongly recommend that you try it out.

0:12:51.770,0:12:54.425
Especially, if you've never played with Nixie tubes,

0:12:54.425,0:12:57.550
this things are really, really neat and they're not that expensive.

0:12:57.550,0:13:00.040
You can get them in all kind of patterns.

0:13:00.040,0:13:01.140
Doesn't have to be numbers.

0:13:01.140,0:13:04.180
Sometimes you can have them as bars or something else.

0:13:04.180,0:13:08.725
So I strongly recommend that you try this out, and then you see what you can do with it.

0:13:08.725,0:13:11.740
Just be very, very, very careful.

0:13:12.890,0:13:17.170
>> Well, I hope you enjoyed this episode playing with flash circuits and

0:13:17.170,0:13:21.550
Nixie tubes and I hope that we learned a thing or two about how these things operate.

0:13:21.550,0:13:24.430
Unfortunately, I'm going to have to break this video up again into

0:13:24.430,0:13:26.585
multiple sections because YouTube doesn't allow

0:13:26.585,0:13:28.985
me to upload anything that's more than 15 minutes.

0:13:28.985,0:13:31.880
But if you guys watch these videos and upper rank them,

0:13:31.880,0:13:34.300
then YouTube will eventually allow me to put

0:13:34.300,0:13:38.030
the entire episode in one video so you don't have to keep clicking.

0:13:38.030,0:13:40.420
So, please make sure you discuss this in

0:13:40.420,0:13:43.720
the comment section and also don't forget to answer

0:13:43.720,0:13:49.480
the quiz that I asked about why the neon light flashes as opposed to LED that doesn't?

0:13:49.480,0:13:51.150
Whoever gets the answer right,

0:13:51.150,0:13:54.515
will choose the next topic of the next episode.

0:13:54.515,0:13:55.810
We have a lot of videos,

0:13:55.810,0:13:57.130
a lot of equipment to review,

0:13:57.130,0:13:59.245
and a lot of interesting things coming in the future.

0:13:59.245,0:14:00.520
So, make sure you check back,

0:14:00.520,0:14:03.850
subscribe and I'll see you soon.