"Vacuum Tube" Tesla Coil - TOY

[FuzzyTomCat]

Vacuum Tube Information

Hi everyone,

Here is one source for the required vacuum tubes for the "Vacuum Tube Tesla Coil" if you haven't already found one, there usually in old or antique radio parts stores.

10 Triode ST Shape ($69.95 US) ST type
81 (ST) ($15.95 US) ST type
10 Triode Globe Shape ($99.95 US)
81 Rectifier Globe Shape ($89.95 US)

The difference in the two referenced is the exterior globe style ...

Glen

[Electrotek]

Hi everyone,

Here is one source for the required vacuum tubes for the "Vacuum Tube Tesla Coil" if you haven't already found one, there usually in old or antique radio parts stores.

10 Triode ST Shape ($69.95 US) ST type
81 (ST) ($15.95 US) ST type
10 Triode Globe Shape ($99.95 US)
81 Rectifier Globe Shape ($89.95 US)

The difference in the two referenced is the exterior globe style ...

Glen

The Tubedepot. That's a great find. They have the 117L7 for $7.95, and other tubes I like.

[FuzzyTomCat]

The Tubedepot. That's a great find. They have the 117L7 for $7.95, and other tubes I like.

No problem, I found some manuals (PDF's) that you or some of the other members of Energetic may find helpful in this project or other builds using "vacuum tubes" ....

Telefunken Tube Manual 1930-1931 "German Only"
RCA Tube Manual 1933
Western Electric Tube Manual 1933
RCA de Forest Transmitting Tube Manual 1934
RCA Vacuum Transmitting Tube Manual TT-3 1938

Meissner "How To Build" Instruction Manual 1953 "Highly Recommended"
UTC Transformer Catalog w/ Cross Reference 1963
Inside the Vacuum Tube By John Rider 1945

Enjoy,
Glen

[FuzzyTomCat]

Power Transformer Information

Hi everyone,

I've been able to finally source the required transformer (or equal) for the "Vacuum Tube Tesla Coil" with 350 to 500 volt secondaries including optional 120 volt and 120-240 volt primary windings.

"Hammond Manufacturing" (or equal)

5 volt rectifier filament 1.25 amp (one required)
6.3 volt tube filament 1.25 amp (one required)

#260M 250va 350v sec - 120-240v primary
#278X 200va 400v sec - 120v primary
#279X 150va 425v sec - 120v primary
#282X 200va 500v sec - 120v primary
#378X 200va 400v sec - 120-240v primary
#379X 150va 425v sec - 120-240v primary
#382X 200va 500v sec - 120-240v primary

Hammond Mfg. - Transformer Index
260 series
"Classic" 263-282 series
"Classic" 300 series
"Classic" 700 series HV-Plate Type ( wo/filament sec.)

Glen

[FuzzyTomCat]

Yes, I'm actually going to do it !!

Hi everyone,

I started to get my parts finally for my first open source published device build, something FUN .... I'll see if this magazine article "How To Build It" (Jan, 1932) titled "Vacuum Tube Tesla Coil Does Fascinating Stunts" actually works, I cant wait to see sparks and burn my fingers as the author stated I think eveyone should enjoy just a little electrotheropy once in awhile .... maybe see some electrons !!
__________________________________________________ _______________
Shopping List -

1) board 18 x 10
2) tube 8" long x 4" OD
3) tube 11" long x 2 1/2" OD
4) (2) ux vacuum sockets (4-pin)
5) transformer 110v pri, 500v sec w/ (2) 6.3v filament
6) (1) #81 rectifier vacuum tube
7) (1) #10 amplifier - oscillator vacuum tube
8) wood tube supports
9) (1) 5000 ohm resistor 5 watts (wire wound)
10) (1) 1 mf capacator 600 volt ( type ??)
11) 50 ft #16 awg wire
12) 700 ft #28 awg wire
13) 120 volt 15 amp plug 6 foot cord end
__________________________________________________ _______________

The first Item (5) is a Hammond 282X transformer 200va 500v sec - 120v primary 10.6 LB's from Fair Radio Sales Co. Fair Radio Sales Company Inc. $98.57 + $13.27 SH (drop shipped from Hammond MFG) for a total $111.84 Dollars US (W/ no problems)




The second item (6) is the RCA 281 (globe) which I substituted a equal, nos-81 (ST) the only difference is in the glass globe [a generic # 81 in a ST type globe] came in the original box.
NOS 81 (ST)




The third item (7) is the RCA 210 (globe) which I substituted a equal, nos-10 (ST) the only difference is in the glass globe [a generic # 10 in a ST type globe]
NOS 10 (ST)




These Vacuum Tubes came from the Tube Depot Welcome to TubeDepot.com! the nos-81 (ST) was $15.95 and the nos-10 (ST) was $64.95 + $3.95 SH for a total $84.85 dollars US (W/ no problems)

I'm having problems sourcing item #4 the UX vacuum tube socket bases that can be board mounted, the only ones I can find at this time are chassis type mount with solder bases underneath, anyone with source suggestions ??

I still have several small items to purchase and some spare time but this should be a electrifying experience, whoa !!

Glen

[FuzzyTomCat]

Design Notes

Hi everyone,

Here is the "Shopping List" and some items that may need some explanation due to the age (1932) of the materials specified.

1) Board 18" x 10"
2) Cardboard Tube 8"Lg x 4" O.D.
3) Cardboard Tube 11"Lg x 2 1/2" O.D.
4) (2) UX style Vacuum Tube Sockets - 4 pin
5) Transformer 110v pri, 500v sec w/ (2) 6.3v filament windings
6) (1) #81 Rectifier Vacuum Tube (#281)
7) (1) #10 Amplifier - Oscillator Vacuum Tube (#210) "OPTION [4]"
8) wood tube supports
9) (1) 5000 ohm Grid Leak 5 watts
10) (1) 1 uf/MFD Condenser 600 volt
11) 50 ft #16 awg D.C.C. Wire
12) 700 ft #28 awg D.C.C. Wire

"Design Notes" (Component Reference - Hawkins Electrical 1917)

1) "D.C.C. Wire" - Double Cotton Covered Magnet Wire [1]
2) "Grid Leak" - Tinned Iron Wire wrapped on a Asbestos Tube [2]
3) "Condenser" - Film (Tin Foil - Paraffined Paper, layers) or Electrolytic type [3]
4) "Vacuum Tubes" - 700 Volt (maximum) Replica Build, Transformer not to exceed "Tube" voltage (match all components for build voltage) [4]
5) "UX style Vacuum Tube Sockets" (4-pin) - Quanity of (3) required if additional power Vacuum Tube wanted for future


[1] Substitution - 1KV Magnet Wire - Essex ® Copper Magnet Wire, GP-200 (Polyester / Polyaide Imide) or POLYURETHANE/NYLON COATED CLEAR
[2] Substitution - Wire wound Resistor - Ceramic or Porcelian Tube
[3] Substitution - Capacitor 600v-1000v
[4] "Additional Power" - wired in parallel (1) additional #10 amplifier (#210) - Oscillator Vacuum Tube for a total of (2)

Hope this helps for those that may be attempting a replica device build.

Best Regards,
Glen

[boguslaw]

Very interesting ground connection ! also how does vacuum tube 210 works here ?

I think it may be OU device with just missing few parts...

[FuzzyTomCat]

Very interesting ground connection ! also how does vacuum tube 210 works here ?

I think it may be OU device with just missing few parts...

Hi boguslaw,
The ground connection is just one of the weird things on this 1932 "toy" (chassis "and" earth ground ?) and as far as the #210 Amplifier - Oscillator Vacuum Tube and adding a additional one for more power from 900-1600 mW (milliwatt) to 1800-3200 mW, I have no clue.

If you check the positioning of this #210 tube with it's interior tube plate parallel to coil 1 & 2 in figure 2 and looking at the base orientation reversed for #281 Rectifier Vacuum Tube by the transformer is this a accident by just illustrating the device for replication or is there a reason behind these anomalies.

OU good question ... there are several devices in threads here like DrStiffler's High Voltage from Thin Air? as a example that may with modifications work with this.

The other strange item is all the known "Vacuum Tube Tesla Coils" or VTTC builds all use other tubes ....

211 or VT-4C
250 (TL or TH)
304 (TL or TH)
572B
803
805
806
810
811A
812
833 (A or C)
PL504
PL509
PL519
6GJ5
6HF5
6JB6
6JE6
6JM6
6JG6
6CD6
6DQ6
EL509
6LX6
6DQ6
24JE6A
6JB6A
30KD6
40KG6
36MC6
26HU5
6146A
6P45S
GM-70
GK-71
26HU5
GU-80
GU-81
GD-400

This is far as I can find the "only" VTTC build that uses these tubes ..... and any VTTC other than this one was built and designed using the above mentioned tubes at least 10 years later.

Best,
Glen

[boguslaw]

So 210 is acting as :
- rectifier ?
- switch ?
- phase changer ?
- delay ?

[morpher44]

harmless toy

It looks like a harmless toy

I love this kind of stuff. Thanks for posting it.

What is so cool about this Tesla coil is that you can both burn yourself
and shock yourself with the same appliance.
And geez, that transformer. Yikes. Kid toy?
Those were the days. :-)

[citfta]

Basic Tube Theory

Hi guys, maybe I can help a little here. I first started working on tube type radios about 50 years ago so I am familiar with how tubes work. First we have to remember tubes are voltage amplifying devices as opposed to transistors which are current amplifying devices. The 281 tube in the schematic is only a rectifier tube or in modern solid state devices we would call it a diode. Diode meaning it only has 2 parts. It only has a filament and a plate. So how does it rectify the AC to DC. When the filament gets hot it throws off electrons which have a negative charge on them. When the AC voltage on the plate swings positive the electrons are attracted to the plate. When the AC swings negative the electrons are repelled and no current can flow through the tube. As stated in the specs on the tube this tube is only a half wave rectifier. You have to use two for full wave rectification.
Now let's look at the 210 tube. This tube was commonly called a triode because it has three parts. In between the filament and the plate is a screen or fine mesh that is called the grid. By varying the voltage on the grid we can control the flow of electrons from the filament to the plate. If we make the grid positive we will attract the electrons from the filament towards the plate. The higher voltage on the plate will cause the electrons to go past the grid and onto the plate. If we make the grid negative enough we can stop the flow of electrons completely. By the way later tubes used a thin sleeve that was especially coated to give off more electrons. This was placed over the filament and became know as the cathode. At that point the filament was only used to heat the cathode and the electrical circuit was connected to the cathode instead of the filament. The plate was also called the anode. These 2 terms have carried over to our solid state devices.
OK, I hope you have all that. So what is the 210 tube doing in this circuit? When the power first comes on the filaments of the tubes have to heat up. When the filament of the 281 tube gets hot this tube will become a rectifier supplying half wave DC voltage of about 500 volts or so to one side of the capacitor at the bottom of the schematic and also to coil # 1 and on to the plate of the 210 tube. At this point the grid is basically neutral in the circuit so current will start to flow from the filament to the plate and of course on through coil # 1. If the polarity of coil # 2 is wired correctly when current starts flowing in coil # 1 a current of opposite polarity will start to flow in coil # 2. This will cause the grid to go negative and cut off the flow of electrons. When coil # 1 turns off this turns off coil # 2. The resistor allows the charge to bleed off the grid until the tube starts to conduct again and the cycle starts over. This was a long winded way of saying what we have here is a very simple oscillator. By the way the capacitor at the bottom of the schematic is only used to smooth out the DC pulses coming from the rectifier tube. And also Glen you did a great job drawing the schematic.
I looked through the pages you posted Glen and I couldn't find the reference to the 6 HZ frequency you referred to. I think that has to be a misprint because this circuit is going to oscillate much faster than that. I think it would be more like 6 KHZ.
My tube type theory is a little rusty so if someone sees any mistakes I have made please feel free to correct me, but I think I have the basics right. Hope this was some help. Best wishes, citfta

[FuzzyTomCat]

Hi guys, maybe I can help a little here. I first started working on tube type radios about 50 years ago so I am familiar with how tubes work. First we have to remember tubes are voltage amplifying devices as opposed to transistors which are current amplifying devices. The 281 tube in the schematic is only a rectifier tube or in modern solid state devices we would call it a diode. Diode meaning it only has 2 parts. It only has a filament and a plate. So how does it rectify the AC to DC. When the filament gets hot it throws off electrons which have a negative charge on them. When the AC voltage on the plate swings positive the electrons are attracted to the plate. When the AC swings negative the electrons are repelled and no current can flow through the tube. As stated in the specs on the tube this tube is only a half wave rectifier. You have to use two for full wave rectification.
Now let's look at the 210 tube. This tube was commonly called a triode because it has three parts. In between the filament and the plate is a screen or fine mesh that is called the grid. By varying the voltage on the grid we can control the flow of electrons from the filament to the plate. If we make the grid positive we will attract the electrons from the filament towards the plate. The higher voltage on the plate will cause the electrons to go past the grid and onto the plate. If we make the grid negative enough we can stop the flow of electrons completely. By the way later tubes used a thin sleeve that was especially coated to give off more electrons. This was placed over the filament and became know as the cathode. At that point the filament was only used to heat the cathode and the electrical circuit was connected to the cathode instead of the filament. The plate was also called the anode. These 2 terms have carried over to our solid state devices.
OK, I hope you have all that. So what is the 210 tube doing in this circuit? When the power first comes on the filaments of the tubes have to heat up. When the filament of the 281 tube gets hot this tube will become a rectifier supplying half wave DC voltage of about 500 volts or so to one side of the capacitor at the bottom of the schematic and also to coil # 1 and on to the plate of the 210 tube. At this point the grid is basically neutral in the circuit so current will start to flow from the filament to the plate and of course on through coil # 1. If the polarity of coil # 2 is wired correctly when current starts flowing in coil # 1 a current of opposite polarity will start to flow in coil # 2. This will cause the grid to go negative and cut off the flow of electrons. When coil # 1 turns off this turns off coil # 2. The resistor allows the charge to bleed off the grid until the tube starts to conduct again and the cycle starts over. This was a long winded way of saying what we have here is a very simple oscillator. By the way the capacitor at the bottom of the schematic is only used to smooth out the DC pulses coming from the rectifier tube. And also Glen you did a great job drawing the schematic.
I looked through the pages you posted Glen and I couldn't find the reference to the 6 HZ frequency you referred to. I think that has to be a misprint because this circuit is going to oscillate much faster than that. I think it would be more like 6 KHZ.
My tube type theory is a little rusty so if someone sees any mistakes I have made please feel free to correct me, but I think I have the basics right. Hope this was some help. Best wishes, citfta

Hi citfta,

Thanks for the "great" explanation of the circuit because I'm really rusty on vacuum tubes, I made a 100w amplifier 35 years ago so it's been a long time. I think your correct on the frequency being much higher but the article does say 6 Hz on page 141 or the 5th page above the "Miniature Submarine" article.

Vacuum Tube Tesla Coil Does Fascinating Stunts




This should be fun to build and check it out with a scope to see whats going on

Best Regards,
Glen

[citfta]

6 HZ or 60 HZ

Thanks Glen, I didn't see that page when I looked. That must be a misprint then because the output of the transformer has to be 60 HZ since it is running off regular AC power. Or I guess in Europe it would be 50 HZ. The oscillator circuit is converting that into high frequency oscillations. Good luck on your build. Your research abilities to find this old stuff are really great. I have enjoyed your other posts about Tesla very much. citfta

[Mark]

Nice little project you've got going Glen. I hope you will posts some videos.

[barbosi]

Hi guys, maybe I can help a little here. I first started working on tube type radios about 50 years ago so I am familiar with how tubes work. First we have to remember tubes are voltage amplifying devices as opposed to transistors which are current amplifying devices. The 281 tube in the schematic is only a rectifier tube or in modern solid state devices we would call it a diode. Diode meaning it only has 2 parts. It only has a filament and a plate. So how does it rectify the AC to DC. When the filament gets hot it throws off electrons which have a negative charge on them. When the AC voltage on the plate swings positive the electrons are attracted to the plate. When the AC swings negative the electrons are repelled and no current can flow through the tube. As stated in the specs on the tube this tube is only a half wave rectifier. You have to use two for full wave rectification.
Now let's look at the 210 tube. This tube was commonly called a triode because it has three parts. In between the filament and the plate is a screen or fine mesh that is called the grid. By varying the voltage on the grid we can control the flow of electrons from the filament to the plate. If we make the grid positive we will attract the electrons from the filament towards the plate. The higher voltage on the plate will cause the electrons to go past the grid and onto the plate. If we make the grid negative enough we can stop the flow of electrons completely. By the way later tubes used a thin sleeve that was especially coated to give off more electrons. This was placed over the filament and became know as the cathode. At that point the filament was only used to heat the cathode and the electrical circuit was connected to the cathode instead of the filament. The plate was also called the anode. These 2 terms have carried over to our solid state devices.
OK, I hope you have all that. So what is the 210 tube doing in this circuit? When the power first comes on the filaments of the tubes have to heat up. When the filament of the 281 tube gets hot this tube will become a rectifier supplying half wave DC voltage of about 500 volts or so to one side of the capacitor at the bottom of the schematic and also to coil # 1 and on to the plate of the 210 tube. At this point the grid is basically neutral in the circuit so current will start to flow from the filament to the plate and of course on through coil # 1. If the polarity of coil # 2 is wired correctly when current starts flowing in coil # 1 a current of opposite polarity will start to flow in coil # 2. This will cause the grid to go negative and cut off the flow of electrons. When coil # 1 turns off this turns off coil # 2. The resistor allows the charge to bleed off the grid until the tube starts to conduct again and the cycle starts over. This was a long winded way of saying what we have here is a very simple oscillator. By the way the capacitor at the bottom of the schematic is only used to smooth out the DC pulses coming from the rectifier tube. And also Glen you did a great job drawing the schematic.
I looked through the pages you posted Glen and I couldn't find the reference to the 6 HZ frequency you referred to. I think that has to be a misprint because this circuit is going to oscillate much faster than that. I think it would be more like 6 KHZ.
My tube type theory is a little rusty so if someone sees any mistakes I have made please feel free to correct me, but I think I have the basics right. Hope this was some help. Best wishes, citfta

Thanks for explanations citfta.
Regards.