AC-DC rectifier and Non-Inverting AC amplifier

[quartz69]

i want to design the full bridge ac-dc rectifier...what type of diode is most reliable?
or can i just the random diode...how about the Zener diode??

for the non-inverting AC amplifier, what type of op amp that i need to use to design the circuit.....

basically my input is too small..is about 50mV...is that possible that i can get around 7 or 8 V at the output of the non-inverting ac amplifier
???

 

[quartz69]

please help me in this one guys..i really need your help...
for an expert, i'm looking forward for your comment..

 

[karesz]

Hi,
To make clear basis:
AC= alternating current, means the polarity is changing an changing (think pls on a sinus form)...
DC=direct current, No polarity is changing in the time!
Inverting ampl means in practicum, that you can apply it only for DC, it will even through amp change the signal polarity
(& as bonus does amplify too)!... What do you really need, how about frequency...?
K.

 

[quartz69]

Thanks karesz...

to make things clear, i just explain my project...
i want to make a charger..using the hand-cranked method (as generator to generate voltage)...the output of generator is too small which is 35 mV (RMS) in AC...
so my lecturer asked me to change that 35 mV (AC) to 8 V (DC)...because that is the portable charger, i just need the simple and small circuit..

my idea to amplify the voltage and then convert it to DC..

could you please give any idea about my method or give any other suitable options that may help me...

 

[karesz]

Jo,
and from wher have you to take the energie for your amplifier pls?
K.

 

[quartz69]

energy for amplifier??
which amplifier?

sorry, I don't get it

 

[karesz]

...my idea to amplify the voltage and then convert it to DC..

Maybe you can scatch-drow pls what your system idea is.
K.

 

[quartz69]

my idea is to get the output of 8V dc from whatever circuit that has the input of 35mV ac...

is that possible?

my friend give me an idea by amplify the 35mv ac voltage using whatever circuit (using common-source amplifier or any other way). then when i get bigger enough AC voltage, i want to convert it to DC...

my second idea is to convert the 35mV ac voltage to dc voltage using the full-bridge rectifier and i already done it and i get 10mv dc voltage...so,next i want to amplify it...
first i tried using the boost converter but i had a problem using the mosfet...so,maybe there are any other way...


maybe my whole methods are not suitable..maybe you can come out with the suitable method as long as i can change that 35 mV ac voltage to 8V dc voltage using the simple circuit...because my lecturer want the simple circuit, sort of like portable one..

 

[karesz]

So far as I understand your ideas, for me is nothing of their to realize_sorry...
You will be a wizarder.
K.

 

[FvM]

Your skipping the quantity current respectively power/energy in your question.

Basically 35 mV AC can be converted to 8 V DC. But conservation of energy as a fundamental physical law can't
be tricked. If you want to take out 10 mA at 8 V, you have to put in about 2.5 A at 35 mV (considering some losses).