Joule Ringer!

[hartiberlin]

hi Conrad,
do you also get somewhere in your circuit the
scopeshot from Lasersaber in his video:
http://www.youtube.com/watch?v=PoEXCweMxhk

Look at around Minute 6:00 and ongoing.

Is this the voltage at the Basis to emitter of the transistor ?

Or where did he measure this voltage ?

Please let uns know.

Many thanks.

Regards, Stefan.

[conradelektro]

Scope shots of xee2 type Joule Ringer circuit, the problems.

@ Stefan (hartiberlin) and all interested parties:

The problem with this circuit and scope shots: the circuit is very very very sensitive.

Removing the 4700 μF cap increases the power consumption to about 60 mA.

Introducing a 10 Ohm shunt at the positive side of the 4700 μF cap (as Stefan suggest) also increases the power consumption to about 60 mA. That is the reason why I put the 10 Ohm shunt between the power supply and the circuit. The 4700 μF cap itself determines important parameters of the circuit, like frequency and transistor on time. And if one separates the 4700 μF cap, e.g. with a 10 Ohm shunt, the circuit behaves differently. I can not measure over a 1 Ohm shunt, my scope is not that good.

I can not measure anything else than straight 12 Volt over the 4700 μF cap. That might be a problem of my scope or a lack of skill. Or the 4700 μF cap dampens all spikes.

We have to come up with an "indirect way" to measure input to the the 4700 μF cap. Or we might conclude from the spikes over the 10 Ohm shut between the power supply and the circuit, that the 4700 μF cap "absorbs" the spikes (we see the inverse of these spikes on the shunt). But even if that is the case, the energy in the 5 μsec spikes is very little.

My guess, the short "transistor on time" and the low frequency of this "on time" around 160 Hz is the key to understand the circuit and its low power consumption. Keep in mind, the lamp is rather dim! And when the power consumption goes up to 60 mA (e.g. by removing the 4700 μF cap), the lamp immediately becomes very much brighter (because energy input goes up 60 times).

Greetings, Conrad

Added: I think LaserSaber measured over collector-emitter as I did above.

[hartiberlin]

Hi Conrad,
just forget the 10 Ohm shunt and just measure alone
the voltage at the cap WITHOUT any power supply connected.

To do this well, just set the scope input channel to AC (not DC)  and then use the
best amplification of your scope channel so you can see also millivolt
changes.
Setting the scope to AC lets you filter out the overlayed 12 Volts DC part,
so you don´t need to offset this voltage and can go
further up into the amplification settings of the scope.

I really need to see the cap voltage alone in the selfrunning mode
with a resolution of around at least 50 MilliVolts/div
and a horizontal deflection setting of around 10 millisec/div and another of 10 usec/div.

Many thanks.

Regards, Stefan.

[hartiberlin]

P.S: You need to really show the millivolt changes in the 12 Volts voltage of the 4700 uF cap
when it is not connected to the power supply.

Only this way we can see, if the cap is charging up, when the spikes occurr.

To really see this you HAVE to set your scope input to AC to be able to amplify it enough
and to compensate for the 12 Volts DC it is already getting...
So we really need to see any millivolts spikes there on the 12 Volts cap voltage.

Many thanks.

[conradelektro]

Finally, a scope shot over the 4700 μF cap

@ Stefan (hartiberlin) and all interested parties:

Thanks to Stefan's coaching I managed to do a scope shot over the 4700 μF cap with and WITHOUT POWER SUPPLY.

My scope has a high trigger threshold, therefor a bit of the left side of the signal is missing. The pre-trigger does not work in single shot.

I placed a 1 Ohm shunt after the cap as Stefan suggested and the frequency went to about 300 Hz and power consumption to 1.5 mA at 12 Volt. One can not see the 1.5 mV on the scope but the spikes are visible because they are up to 200 mV.

Please let me know what you conclude from this scope shots over the 4700 μF?

Greetings, Conrad

P.S.: Let me know what I could do better in order to see more details over the cap.