Joule Ringer according to xee2

I found a little fly back transformer in a cold cathode lamp driver. With this transformer and a TIP31C transistor I could replicate the circuit from xee2.

Using a bifilar coil instead of the resistor-capacitor combination on the base of the transistor did not improve the circuit.

With the resistor and the capacitor the brightness (and the power consumption) can be adjusted.

With 50 K and 100 nF the consumption is way below 10 mA at 12 Volt, and with 100 K and 200 nF even less (but the lamp is also less bright and stays on for about 180 seconds with the caps).

The original driver needs more than 100 mA at 12 Volt !! I fried the original transistors 2SD1616A, so I moved to a more sturdy TIP31C. Only one collector coil of the little fly back transformer is used.

I will try a Darlington pair soon. Greetings, Conrad

@ conradelektro      You might want to try this circuit. I found it works a little bit better.

@xee2

I could do some power consumption measurements over an 1 Ohm resistor (voltage drop):

The circuit from my last post (with 100K and 200nF) with a CFL needs about 2 mA at 12 Volt. (With my smallest cold cathode lamp it only needs close to 1 mA at 12 Volt.)

With your modification (33K, 10 μF) it needs about 3 mA at 12 Volt and the lamp flickers.


The "stay on time" with a 9400 μF cap agrees with theory:
C = 0.0094 Farat = 9400 μF, 12 Volt, 2 mA
12 V and 0.002A --> 0.024 Watt
0.5 * C * V * V = 0.5 * 0.0094 * 12 * 12 = 0.6768 Joules (Wattseconds) in the caps
0.6768 / 0.024 = 28,2 seconds

In practice the lamp stays on about twice or even tree times as long on the caps because voltage and with that power consumption and brightness decrease as the caps discharge slowly.


The circuit is very sensitive and depends on the lamp, the transistor and the resistor-capacitor combination (with a given transformer and supply Voltage).

Whenever I get the lamp bright (with a certain resistor-capacitor combination) the power consumption goes up to about 20mA or even 200mA, even more depending on the lamp. This also agrees with theory, because my lamps need up to 4 Watt to shine very bright.

Really bad is switching lamps when the power is on, that can fry the transistor.

What I see so far: one can probably bring down the power consumption to may be 0.1 mA by reducing the frequency of the circuit to 50 Hz and adjusting everything very carefully, but then the lamp will be rather dim and prone to flickering. But still, it is a nice way to dimly light a gas discharge lamp with little power. As a novelty item, dimly lit gas discharge lamps look nice and interesting. And it is an interesting and educational experiment. It also teaches you how sensitive the eye is and how difficult it is to judge brightness without a Lumen-meter.

If one wants to light the lamp according to its specified brightness potential, the Watts have to go up to specification. Put the same lamp (unmodified) in a wall socket next to an identical lamp in a Joule Ringer circuit and you will be surprise as to how bright the lamp in the wall socket is (you can't even look at it without hurting your eyes).

Greetings, Conrad

Update on the xee2 Joule Ringer --> Darlington Pair, 0.5 mA at 12 Volt

I could bring down the power consumption at 12 Volt to 0.5 mA with a Darlington pair (2 x TIP31C). The blue cold cathode tube stays rather dim with this circuit and stays on about 1 minute with a 4700 μF cap in agreement with conventional theory. I think to see some flickering, so the frequency must be around 20 to 30 Hz.

C = 0.0047 Farat = 4700 μF, 12 Volt, 0.5 mA
12 V at 0.0005A --> 0.006 Watt
0.5 * 0.0047 * 12 * 12 = 0.3384 Joule (Wattseconds) in the cap
0.3384 / 0.006 = 56.4 seconds

@NickZ: For LEDs I would not use a fly back transformer. A hand wound coil looks more promising and a Darlington pair with two C547B transistors. I think about a coil in principle like a fly back transformer, but fewer turns, on a 25 mm plastic tube. The trick is to get the number of turns just right (may be 300 turns for the HV coil, 40 turns for the driver coil on the collector and 10 turns for the trigger coil on the base of the transistor, for 10 LEDs in a row on the HV coil). For LEDs I also would go down to a 1.2 Volt rechargeable AAA battery instead of a 12 Volt battery or power supply. The interesting part is to get the power consumption below 1 mW. I came up with a "night light" which needs about 2 mW for one white LED (you find it in my posts in the Joule Thief thread).

Greetings, Conrad

P.S: the question is also,
if the bifilar coil from Lasersaber is somehow inducing current
back into the cap, so replacing it with just a cap and a resistor
as Lidmotor and some others have done it
will not show the same recharging effects of the cap as in
Lasersaber´s videos.

So that is really also why we really need a few good scopeshots of the
supply capacitor voltage and also scopeshots of the
current of this cap at a shunt.

Only this way we will find out, if there is any additional recharge
induction is taking place, that will recharge the cap from
this bifilar coil system.

Many thanks.

Regards, Stefan.

Scope shots over 10 Ohm shunt, collector-emitter and lamp of xee2 type circuit.

@ Stefan (hartiberlin) and all interested parties:

The scope shots show a frequency of about 160Hz and very short transistor on times in the order of 5 μsec.

This might explain the low power consumption of about 1 mA and less (the scope and a 10 Ohm shunt show about 1 mA, a good Multimeter and a 1 Ohm shunt show around 0.7 mA).

There are very short spikes in the order of 5 μsec at 160 Hz over the shunt and therefore also on the 4700 μF cap. To expect a real re-charging of the cap by these spikes seems to be a bit bold.

Draw your own conclusions, Conrad

Many thanks conradelektro  !

But you measured it at the power supply.

I just wanted to see it at the selfrunning state,
where it only runs from the capacitor.

But I already see from these spikes,
that the capacitor gets a recharge from the spikes also.

I will post a modified measurement circuit and please measure it like this.
Many thanks again for your great help.

Regards, Stefan.

Scope shots over 10 Ohm shunt, collector-emitter and lamp of xee2 type circuit.

@ Stefan (hartiberlin) and all interested parties:

I will do the scope shot with cap only (no power supply). Here a scope shot that shows in more detail the very short transistor on time.

Conrad