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AC DC converter

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Super_sonic

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What is the best way to implement an AC-C converter, i have very small voltage coming in, around 1V(p-p). I need an efficient method, are there any chips that do the job efficiently.
THanks
 
Use a diode bridge

What about a simple diode bridge? connect 4 diodes so that the ac goes into two facing oposite directions, and combine the output of each pair inot a positive/negative bridge.


Jim
 
yeah i was wondering if there was a more efficient way of doing this, i dont think i can do this cause my input votlage is way too low, the doides will have votlage drops across themm as well and i dont want to use the transformer to step up the voltage.
 
You need to give more details about what you're trying to do - the voltage levels you talking about look more like a signal rather than a power supply, and these are dealt with completely differently.
 
Nah it is a power signal, it coming out of a dynamo where the open circuit voltage at the rotational speed that its gona be operating at will be aproximtley 1V(p-p)
 
Super_sonic said:
Nah it is a power signal, it coming out of a dynamo where the open circuit voltage at the rotational speed that its gona be operating at will be aproximtley 1V(p-p)

You're pretty stuffed then!.

What is it?, and what are you trying to feed from it?.
 
Yeah i think i am, my supervisor gave me that dynamo from his old bike to use, im gona put a turbine through it, and then use it to charge a battery. ill go c him tomorow, thanks for your feedback. Think ill use another type of alternator.
 
Super_sonic said:
Yeah i think i am, my supervisor gave me that dynamo from his old bike to use, im gona put a turbine through it, and then use it to charge a battery. ill go c him tomorow, thanks for your feedback. Think ill use another type of alternator.

If it's a dynamo?, then dynamo's already output DC, alternators output AC and require a rectifier. 1V also seems rather low for a bicycle dynamo?.
 
maybe you're measuring 1vpp in ripple, and there's actually a significantly higher DC current in there too?

I had an old alternator off an antique schwinn, which generated at least 6v without major RPMs ... it was just a little metal canister with a friction wheel on it, which rested on the front wheel hub.
 
Although its called dynamo, a bycycle dynamo actually produces AC, thats what i thought as well. You can find alot of resources on the net aiding that. The votlage is low becasue my RPM is low, usually bycycle dynamos run at around 1000RPM, this should produce about 10V(p-p). my application runs at 100RPM, justDIY do you remeber at approxamtly what RPM you were running?. Im thinking of using gearing system, mabye 10:1 ratio, that should solve it i hope.
 
Super_sonic said:
Although its called dynamo, a bycycle dynamo actually produces AC, thats what i thought as well. You can find alot of resources on the net aiding that. The votlage is low becasue my RPM is low, usually bycycle dynamos run at around 1000RPM, this should produce about 10V(p-p). my application runs at 100RPM, justDIY do you remeber at approxamtly what RPM you were running?. Im thinking of using gearing system, mabye 10:1 ratio, that should solve it i hope.

Yes, you need to spin it MUCH faster, gearing would be a good idea.
 
The dynamo's voltage is proportional to its speed. You're not turning it fast enough.
 
a standard bycycle dynamo produces 6 V ac 500 mA what are you using to turn it ? a water turbine ?
if you run it at 3000 RPM that is 50 turns a second snd so 50 Hz that can be fed into a transformer if you really need to boost it.
 
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Just a question about gear boxes. If lets say, i have a turbine spinning at 100RPM, if i install a gear box of 5:1 Ratio, wouldnt that automaticlly slow down my turbine by about 5 times due to the gear loading. So it wouldnt make a difference. Im thinking that a gear box is used when u dont want your turbine to spin too fast, but still get the same rotational speed on the rotor. am i right?
 
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