3.7 VOLT BATTERY POWERS 56 WATTS

[magnetman12003]

Hi magnetman, thanks for the reply.
I used the SCR test circuit with 12 volt battery, 12 volt incandescent bulb and 290 ohm resistor to gate, to check and see if it was ok, it is ok.
I then rewired the neon and SCR capacitor dump section, just like the test circuit and still no dumping happening.
I have a different oscillator than yours magnetman, using the meissner oscillator to charge the capacitor.
Still, i do not understand why this is not working, maybe the neon i have is not giving enough current into the gate, compared to the neon bulb you are using.
It's one of those green radio shack neons, with plastic encapsulated.
It's this neon. https://www.radioshack.com/products/radioshack-120-volt-neon-green-lamp-2-pack
peace love light

When I was still in the building stages of this particular circuit I tried out many different neon bulbs and found out very quickly that a lot of them turned black rapidly and burned out. The transistor  gave it up also.  Then I tried the B7A neon bulbs and had no further trouble. They never turned black and failed.  So far the finished circuit I have shown has never failed me yet.    I would love to try one of those USB battery chargers that steps up A SINGLE 1.5 VOLT AA battery to 5 volts output.  Connect that to the circuit and see if the 8  seven watt bulbs lite up.  Presently I am using a single 18650 3.7 volt battery inside a USB charger to do this. Like to buy locally instead of out of China.  Know of any retailer?

[gyulasun]

....
maybe the neon i have is not giving enough current into the gate, compared to the neon bulb you are using.
....

Hi Tyson,

Yes this may explain why the thyristor is not turning on. Magnetman's neon type, B7A has a 2mA current when flashes
http://www.farnell.com/datasheets/1657095.pdf ,  common neon bulbs normally have around 1mA or less current.

Your NTE5554 http://www.nteinc.com/specs/5500to5599/pdf/nte5550_58.pdf  is not specified for a minimum gate trigger current, only for a maximum 40 mA, and typically 25 mA,  while the BTW69-1200 is specified as minimum 8mA but this latter type is obviously more sensitive then 8mA the data sheet says if I accept the 2 mA current for the B7A. Of course this 2 mA can be higher if the DC voltage in C1 is higher than 120V in magnetman's setup.

If you have not managed to trigger your NTE thyristor in the meantime, I would suggest considering crowbar circuits that use thyristors, you surely know about such circuits. Here the gate trigger current comes via a Zener diode chosen for the voltage levels involved. See this link: http://axotron.se/index_en.php?page=26

If you happen to have some 15V or 24V Zener diodes at hand, you could put a few of them in series and replace the neon bulb with them. The resistor R1 between the gate and the cathode of the SCR could be say 1-2 kOhm and for Zener safety connect a 4.7kOhm to 10 kOhm resistor in series with the Zener_series_string to limit Zener current. This way you would have higher current injection into the gate than you have from the neon now (maybe the Radioshack neon lamps have a built in series resistor to limit current and this reduces the possibility of triggering the SCR even more?)

By the way, what DC voltage is collected in your capacitor C1 from your oscillator?  80 - 100V?

Gyula

[TinselKoala]

Neons, when the plasma is present, have practically zero resistance. Hence they will draw whatever the current source can supply, even to the point of violent self-destruction. The current specifications like 2mA for the B7A are nominal currents,  that must be limited to that value by the use of a resistor. The B7A has a 30 k current-limiting resistor built in, according to the data sheet linked above,  and the RadioShack 120V neon indicator assemblies also have a resistor in the housing.

common neon bulbs normally have around 1mA or less current.

It is more correct to say that these neons will glow nicely at 1mA or less current, but the current must be limited to this value externally, either by a current-limiting resistor or by using a power source that cannot deliver more current.

If they are allowed to draw more current than the nominal value, several things happen. First the color shifts from the usual reddish-orange toward more red and eventually purple, and if a power arc forms between the electrodes with enough current, they go white and then they explode. Second, with more than the nominal current they heat up, and the electrodes start vaporizing and cause the glass to become blackened or even totally black as the electrode material is sputter-coated onto the glass. I'm sure everyone who have built Bedini circuits with neons have seen their neons glow purplish at times and over time they see the glass become blackened.

If the neon is used to trigger the thyristor, I would suggest using a bare neon, like NE-2 or NE-2a, with no series resistor.

[Ispeed]

Hi mangnetman,

I can see a very good job done by you, weldone. please am from nigeria and am not an electric guy, i want to know if you can help me build a working system board and put the schematic drawing then send it to nigeria i would appricate and ready to pay for the cost. Thanks.

N.B. Please how long does the battery last before it rundown.

[markdansie]

Hi all
I have one really dumb question to ask. How long does a 18650 3.7 volt battery last running these lights and what is the mA of the battery. I.E 2600?


Kind Regards
Mark