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Strobe Lights


deblen

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deblen wrote:

H,

Thanks for all the replies, now you have me wondering about the voltage.

Strobes are had to find in Australia. (240 volt). If I purchase them from the US (110 volt),

To run them I would need to get a 240 to 110 volt convertor, then use this to power them, or do they need to be reduced again to a lowerr voltage.

I think I will put some on the same channel, others on a defferent channel.

Might end up using 6 or 7 LOR Channels on the strobe effect.

Any tips on the voltage setup you are using. Can I just step down to a lower voltage or does it have to be 110 volt.

By the diagram above, it looks like they are 7.5 volt ???

Thanks

Deblen

The best thing to do would be to use a 240V > 110V step down transformers.



My strobes a very rare, mainly mine are defects.
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BadSCR wrote:

Max-Paul
I see what you are talking about, the voltages you give are right,
With the two resistors they devide the voltage between them, if there was just one resistor there would be a Full 7.5Volts across it.

With capacitors: Have to use supper position, have to replace the capacitor with a Short, inorder to do the Calculations.




time out for a second. I need to get a better picture of this. Am I right to say that you have a series circuit of 3 items? a 20 ohm resistor, a 16 ohm resistor and a strobe, is this not correct? Or, are you talking about a voltage divider with the strobe circuit in the middle of the two resistors?

If it is the first were all three are in series, then the cap becomes short of mute. For it will spend some time charging via the charging circuit and a short time discharging. But in either case the charging circuit will remain an almost constant load.

Still for this exersize it would be nice to know what the supply voltage is, what the voltage drop is across each item (R1, R2, & S1).



Max
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Ok, Lets recap.

Original Strobe: Vs-----> R1 ----> Strobe -----> Ground
Running on 7.5Vdc and pulling 375mA
The 20-ohm 1-watt resistor has 7.49Vdc drop (7.49Vdc*375mA=2.81Watts)



Modified Strobe: Vs-----> R1 ----> R2 ----> Strobe -----> Ground
Added a 16-ohm 5-watt resistor in series with the 20-ohm resistor.
Running on 7.5Vdc and pulling 208mA
The (R1) 20-ohm 1-watt resistor has 4.16Vdc drop (4.16Vdc*208mA=0.865Watts)
The (R2)16-ohm 5-watt resistor has 3.33Vdc drop (3.33Vdc*208mA=0.693Watts)
R1+R2=Vs 4.16Vdc+3.33Vdc=7.49Vdc kirtchovs law


I added a resistor and it fixed the over heating problem with the 20-ohm resistor.
I don't fully understand this strobe, There is some kinda feedback loop.

The pic is the Original Strobe schematic.








Attached files 172199=9858-Strobe Schem.jpg

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Well all I can say is that from the math. It appears that only about .01 volts is being applied to the strobe it's self. And I am having problems with the thought that this circuit could run on that low of a voltage. With the charging and firing of the strobe in A-stable mode. I would think that the load would be fairly constant. And the turning on and off of the primary side of the transformer more than likely will be in the Khz range. This would leave us with a fairly predictable reading on a DVM or even a VOM. Though the true voltage drop might be slightly higher, but we are not seeing this in this case. So the question is, what is the true voltage being applied to the strobe.

In your reply. You state the voltage across R1 and R2. Is this a physical value or a calculated value? Did you do a physical voltage reading across the strobe?

As for the feedback. Well one case is the oscillator that is jacking up the supply voltage to a few hundred. The second feedback is a simple one of monitoring the voltage across the cap via the neon bulb.

Max

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The reading are physical. (I use another DVM thinking that the first was wrong)

The strobe makes a high pitch noise

some other readings:
The transistor has 1.48Volts drop from C to E
The transformer has 1.63Volt drop on the primary side

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Looks like time for a O'scope to get some better understanding what is going on. I wonder if some of this voltage you are seeing is in part is the CEMF from the transformer. If I was to add up the voltage of both the transformer and the NPN transistor, we have 3.12 volts across the strobe unit. Which puts us about 3 volts above the applied voltage and the only way that could be is that CEMF is involved.

I suppose you will need to do like I did when I converted a string of 35 lamps to 35 LEDs. I know that my LEDs are suppose to be max operating current of 24mA.
And with no filter cap I know that the max peak voltage and hence max peak current draw will be more than my DVM will show. So, I have settled for about 19mA and adjusted my limiting resistor so that I do not exceed this current level. Much different than what I calculated.

Do you know what is the max current rating of the strobe?

Interesting problem, thanks for sharing.

Max

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I do need a 2ch O'scope, just can't seem to find the money to drop onto a good one.

I have no specifications on the strobes, other-then is says 12Vdc on the bottom.

"I wonder if some of this voltage you are seeing is in part is the CEMF from the transformer" Thanking the same thing.




ps: I love your Icon pic under your name, Very Cool. :P

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Well I lifted it off another user. I forgot which forum he was on because I didnt want to crowd in on his use of it. Well turns out he is on this forum. NWSanta is a member here and it was from him I lifted the advatar from.

Ya, I love it too. Love the look and dropped jaw when puss sees the tassel wiggle. Then the iris grow wide open. The slow first couple slaps and then the rapture of multi fast slaps at it. It's great.

Sorry NWSanta, just had to grab it. My only sarrow is that I cant seem to be able to use it any where else that I frequent. Would love to use it everywhere else too.

Max

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