converting ac to dc

[ovr50]

I have an ac generator producing .1amp and .1volt. Is it possible to convert this to dc and have anything left. Yes that is one tenth, if so, what would I need to do? Any help would be appreciated.
The measurements are correct, it's a project scale model battery charger that I would like to see work. If it is not possible to convert such low current then what is the lowest amount of voltage/amperage that can be switched to dc?

 

[Nigel Goodwin]

I suggest you give more details, those figues sound completely unlikely?.

 

[audioguru]

The voltage is too low for a rectifier.
What are you going to do with only 10mW?

 

[mvs sarma]

I am yet to imagine a generator (alternator) which could produce 0.1volts at 0.1amps AC !!!! perhaps multimeter kept in open postion canshow some readings randomly -- ( not to offend the originator. ) or is it ECG probe's outputs ona human body. ??? here also 0.1 amp is not possible. theoritically possible with active rectification methods.

 

[Hero999]

Perhaps ihe wants to power a pic or CMOS project.

Maybe you could build a transformer to step it up to a reasonable voltage, then add a rectifier and filter capacitor like you would with a mains power supply.

 

[philba]

or perhaps it's a homework assignment where the teacher is trying to get the students to think about real world issues like voltage drop across rectifiers and so on.

 

[RODALCO]

Need to see more info here, genrator? alternator?
.1 Volts and .1 Amps is nothing to work with.
Even an elcheapo 1.5 Volt toy motor will generate more when driven externally.
A stepper motor will produce a lot more voltage as long the correct pole pairs are used.

 

[audioguru]

Hero knows how to convert it.
A 1:50 transformer will give a 5VAC/2mA output that can be rectified and filtered to power something that doesn't use much power.

 

[mvs sarma]

Hero knows how to convert it.
A 1:50 transformer will give a 5VAC/2mA output that can be rectified and filtered to power something that doesn't use much power.

Hi Sir,

that is fine. how does he make a transormer and for what frequency?

 

[kpsoneji]

hello uncle scrooge i would like to ask u can we use a simple ckt of a resistor in series and a capacitor in parallel

 

[kpsoneji]

Hero knows how to convert it.
A 1:50 transformer will give a 5VAC/2mA output that can be rectified and filtered to power something that doesn't use much power.

hello uncle scrooge i would like to ask u can we use a simple ckt of a resistor in series and a capacitor in parallel

 

[audioguru]

hello uncle scrooge i would like to ask u can we use a simple ckt of a resistor in series and a capacitor in parallel

A resistor feeding a capacitor is just a lowpass filter. It won't stepup the voltage like a transformer and it won't convert the AC to DC like a rectifier.

I think the original post has been edited and now says it is for a battery charger. It doesn't say how small is the battery but I have never seen a tiny rechargable battery with only 2.8mA for its charging current.

If the 0.1VAC/100mA was transformed to 2VAC/5mA, rectified and filtered to 1.4VDC/2.8mA then it could charge a single Ni-MH AAA cell (900mAh) for 2 weeks to fully charge it.

 

[mvs sarma]

I have an ac generator producing .1amp and .1volt. Is it possible to convert this to dc and have anything left. Yes that is one tenth, if so, what would I need to do? Any help would be appreciated.
The measurements are correct, it's a project scale model battery charger that I would like to see work. If it is not possible to convert such low current then what is the lowest amount of voltage/amperage that can be switched to dc?

Hi,

please come forward --what is this funny generator/alternator --give some details or an image/schematic.
after the post you are silent--

 

[kpsoneji]

A resistor feeding a capacitor is just a lowpass filter. It won't stepup the voltage like a transformer and it won't convert the AC to DC like a rectifier.

I think the original post has been edited and now says it is for a battery charger. It doesn't say how small is the battery but I have never seen a tiny rechargable battery with only 2.8mA for its charging current.

If the 0.1VAC/100mA was transformed to 2VAC/5mA, rectified and filtered to 1.4VDC/2.8mA then it could charge a single Ni-MH AAA cell (900mAh) for 2 weeks to fully charge it.

cant we use ic 7805? as if we use transformer ckt cost high what u say

 

[nura100]

Hello Kpsoneji

i don't know how you'd use a 7805 Linear Positive Regulator with the above setup,

7805 reg would need minimum of 2.5 Volts more than its output Voltage, and the regulator itself would consume some current for its internal circuitry.

the thread starter has to respond to these ideas and furnish more details.

nura

 

[audioguru]

cant we use ic 7805? as if we use transformer ckt cost high what u say

The minimum input voltage for a uA78L05 is 7.0V.
The 0.1VAC needs to be stepped up many times somehow, so use an expensive transformer. At 6VAC it can be rectified and filtered into 7.08VDC. The current is reduced to 1.2mA but a uA78L05 regulator has an operating current of from 3.6mA to 6mA so it will overload the puny amount of current available. A voltage regulator isn't needed for a battery charger anyway.

 

[kpsoneji]

Hello Kpsoneji

i don't know how you'd use a 7805 Linear Positive Regulator with the above setup,

7805 reg would need minimum of 2.5 Volts more than its output Voltage, and the regulator itself would consume some current for its internal circuitry.

the thread starter has to respond to these ideas and furnish more details.

nura

hey tell me the difference between 6v zener diode and ic 7806?

 

[kpsoneji]

A resistor feeding a capacitor is just a lowpass filter. It won't stepup the voltage like a transformer and it won't convert the AC to DC like a rectifier.

I think the original post has been edited and now says it is for a battery charger. It doesn't say how small is the battery but I have never seen a tiny rechargable battery with only 2.8mA for its charging current.

If the 0.1VAC/100mA was transformed to 2VAC/5mA, rectified and filtered to 1.4VDC/2.8mA then it could charge a single Ni-MH AAA cell (900mAh) for 2 weeks to fully charge it.

hey tell me the difference between 6v zener diode and ic 7806?

 

[agent420]

hey tell me the difference between 6v zener diode and ic 7806?

One has one more leg than the other.

 

[audioguru]

A zener diode wastes power, especially when the load isn't using much current. A series voltage regulator IC passes only the amount of current that the load uses.