Author Topic: No current voltage divider  (Read 2215 times)

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Offline Steven DouglasTopic starter

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No current voltage divider
« on: March 08, 2015, 05:33:46 pm »
So first off I'm using a 12 volt power supply, going to be a battery. I'm using a 555 timer to drive a oscillation circuit for a HV drive. I want to use a voltage divider to power a 6 volt transistor, off of the out pin on the 555. But also at the same time i do not want to have current flowing across the second resistor to ground, it just seems to  be a waste of power. Does anyone have any idea how to overcome this, but still keep a good signal going to the transistor?

I would like to just use the one transistor for the switching it is a TIP42c I have had it hooked up through a 1k resistor to the base from the out pin and it works fine but once i have made my device I want it to last as long as possible, so im trying to meet the ratings required rather than going overboard. I thought of using a voltage regulator but I also thought by using one it would cut out the signal and just give me a constant DC voltage.
 

Offline JohnnyBerg

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Re: No current voltage divider
« Reply #1 on: March 08, 2015, 06:19:42 pm »
Strange story, i cannot make not much of it. You do not want to waste power in a resistor to ground, but use a TIP42C, that, per definition, has a lot of losses?

Perhaps a schematic could help.
 

Offline retrolefty

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Re: No current voltage divider
« Reply #2 on: March 08, 2015, 06:40:07 pm »
Short of providing a schematic drawing, any feedback you get will be pretty speculative.
 

Offline gdewitte

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Re: No current voltage divider
« Reply #3 on: March 08, 2015, 07:52:21 pm »
+1 for a schematic. Per Ohm's Law, a resistor with zero current through it has no voltage across it. While you can minimize the current in a voltage divider by using high-value resistors, you need some current for it to work.
 

Offline Anand

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Re: No current voltage divider
« Reply #4 on: March 08, 2015, 09:41:51 pm »
I think you're looking for a 6V regulator (search for an adjustable regulator, with an ADJ pin), connected from the battery (Vin pin) to the MOSFET (Vout pin) and enabled (EN pin) from the output of the 555.
trashf.
 


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