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Quick question about Daedal's circuit

o_DEATH_ANG3L_o

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Is the voltage on the load supposed to increase with less resistance? I know the current increases but is the voltage supposed increase as well? I tested a white LED and at max pot resistance. The voltage is 3.45 volts at 36 mA. I turn the pot to its least resistance and I get 4.30 volts at 127 mA. Does this sound correct or no?
 



Gazoo

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Yes, the voltage will change with the changes in current.
 

o_DEATH_ANG3L_o

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Gazoo you are awesome. I love how fast you reply ;D. Anyways yeah did that sound about right? The figures for the white LED? I just ordered an Aixiz module today and as you can tell I am taking this slowly because I want to get it right the first time. So based on those figures, the LD should be okay right?
 

Gazoo

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Right...it all sounds good. Just make sure, of course, to monitor the current of the LD. You will be fine...
 

o_DEATH_ANG3L_o

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Ok thanks Gazoo :D. But if I am supposed to solder the LD to the capacitor,(to prevent disconnecting of the LD) how would I monitor the current? It may sound like a dumb question but right now I have everything on a bread board with easy access to everything. Also those GB LDs are rated 130 mA. What would be a safe level before that and still have burning power? Maybe 115-120. I dont wanna push it too much ya know. Well thanks again and hopefully you can clarify these last(annoying)questions.
 

Gazoo

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I answered your question on how to measure current in your other thread.. ;) Use the 1 ohm resistor...at least 1 watt. Radio Shack has them... with a rating of 10watts. It's overkill but it will work.

The diode will have nice burning power at 160ma's. Don't let it get hot.
 

o_DEATH_ANG3L_o

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OMG!! :eek: So with the GB LDs being rated at 130 mA, you can push them to 160 mA? Wow that is crazy. Although I do not think my PSU can push that much because I had 4 white LEDs and I was only able to get 127 mA and that is at least resistance of the pot. But then again the LEDs were still really bright :-?. I dunno I am gonna give it a go when I get my module and LD. but only reading 127 mA on 4 LEDs was weird to me. What do you think?
 

Gazoo

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Well here's the thing, you said you measured around 9.5 volts on the power supply while powering Daedal's circuit with a load on it...right? But isn't the highest voltage output of your supply 12 volts? I just now thought of it, but if this is what is happening then your power supply may be bad, or like you said have a weak output on the 12 volt line.
 

o_DEATH_ANG3L_o

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Well on the psu it says 12 volts. The DVD player worked fine and when I tore it apart for the psu I measured it and it was 9.75 volts. Probably right about the weak output though. I mean c'mon here 4 white LEDs only drawing 127 mA? It doesn't seem logical to me. I think I may try a different psu or just use 4 lithium AAs. We'll see though. I'll let ya know the outcome. Well would the LD still burn things at 127 mA?
 




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