Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Hep me make a true rms to dc converter

Status
Not open for further replies.
V

vicky29

Member level 4
Joined
Feb 5, 2005
Messages
75
Helped
3
Reputation
6
Reaction score
2
Trophy points
1,288
Activity points
750
dear all
i want to make a true rms to dc converter to design a "True RMS AC voltmeter" in which the input voltage can be any type of signal like triangular,square or sine etc..and the output should be a dc voltage.i am sending the link of file in which there is a circuit of the rms to dc converter. please help me out to make it work.

also i cant use any costly ics like max536 or lt1966 etc.becuase of cost factor.




thanks alot
waiting for replys.
 

rms to dc converter

When your frequency is limited (near 100Hz) you can use microcontrollers such AVR. They have an ADC integrated in them. You should get many samples from your input signal and to have good precision. your ADC freq. may be near 10 times (1MHz) of original signal with 6 or 8 bits. then your program is work. after getting a new value micro squred and added it to others; countinuing this routine as you think sufficient and other steps to finalize the results then send this to LCD. a micro like Atmega 16 is good choice for beginning
 

rms to dc converter

FYI.
If the sinput sigal is a periodic one, there is a simple way to convert its rms value to DC describing as following:

Employ an AC amplifier to amply the input signal to make sure the output level is above 0.7v, higher amplitude is better. The amplified large signal then is fed into a diode ring mixer as a local oscillator(LO). The input signal is also fed into the mixer and it will be mixed with the LO signal. The DC product of the mixer indicates the RMS value of the input signal since it was multiplied by itself with a factor inside mixer. You can employ a low-pass filter to filt out the DC value from other mixing products(ripple).
 

Re: rms to dc converter

One of the best solution is to use lock-in amplifier because it can cut off great ammount of noise, which is not case in standard measurement devices.
 

Re: rms to dc converter

try these refs. audio amateur 2/83 Rms AC Voltmeter with db converter
by Chares Ulrich
Modern electronics, June,1985 By john t Bailey
If you absolutly need a dc out put try puting an rf probe on the out put.
These designs use the AD536AKH from analog devices, it's abit pricey but low parts count and the cheepest way I have found.
 

Re: rms to dc converter

you can refre to us patent 7002394
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top