Transformer-less power supply 5v or12v.

[imranahmed]

Hi all,

I required transformer-less power supply for ATmega16 based multimeter.

How reliable transformer-less power supply is?

And In my multimeter circuit have below,

1) Atmega16.
2) 4 No. of LEDs.
3) 1 No. of relay 5V.
4) LM324 OP-AMP.

 

[D.A.(Tony)Stewart]

What isolation from common mode (CM) voltages or E field as a CM voltage on high impedance inputs do you expect?
CM Isolation is required.

 

[imranahmed]

Dear SunnySkyguy,

CM Isolation is required.

Please define Common Mode Isolation and Common Mode Voltages?

 

[engineerpervez1]

It is better you should use some PWM high frequency Transformer circuit to get good regulation as well as isolation from the mains supply.
see the topwitch solution by https://ac-dc.power.com/products/topswitch-family/
top switch integrate 50 nos of components in one you can even use some SMD to reduce your circuit size and weight.

 

[imranahmed]

Dear pervez,

Thank you dear it is amazing thing you ever recommend.

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Dear Pervez,

Can you tell me that how I use it or refer some hints?

 

[D.A.(Tony)Stewart]

Is the output near a high electric current pulse common to both V+/-? This is a CM E field.
Does the input and output share a common return conductor. THis is CM signal. e.g. an offline transformerless converter can have CM AC on the DC output but if protected from human access can power lights ok.

There are two modes of voltage, common mode and differential mode.