230 AC to 6 volt 100MA converter without transformer

[thannara123]

Respected Members ,

I am seeking there any cheap and simple ac to ac converter for 230 ac votlt to 6 volt ac with up to 1amp current with a safety circuit . The purpose is t measure or make a digital volt meter.
Please refer good tutorials

 

[barry]

What about a transformer?

 

[KlausST]

Hi,

In headline it is 100mA, in post#1 it is 1A.

Why should a digital voltmeter need 1A?
There are voltmeter circuits consuming less than 5mA.

Klaus

 

[thannara123]

Hi,

In headline it is 100mA, in post#1 it is 1A.

Why should a digital voltmeter need 1A?
There are voltmeter circuits consuming less than 5mA.

Klaus

Sorry I expected the converter up to 1 Amp i don't require 1 Amp , just need for the voltmeter working current only required

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What about a transformer?

Sorry I didn't get you sir

 

[KlausST]

Hi,

a transformer is the most simple solution to convert from AC to AC, usually with safety isolation.

***

So what current do you need now? 100mA? (Why that much?)
And please specify "safety circuit".

Klaus

 

[thannara123]

Hi,

a transformer is the most simple solution to convert from AC to AC, usually with safety isolation.

***

So what current do you need now? 100mA? (Why that much?)
And please specify "safety circuit".

Klaus

okay sir i will select transformer with smallest one. Can you suggest me one smallest and cheapest size ?

I dont require 1m just 5ma as you said .

 

[KlausST]

Hi,

please be more precise.

What do you mean with "1m"?

***
I assume you need 5mA only. Please confirm this.
This is completely different now. For 5mA you may use a capacitive divider or a resistive divider...

Again the question:
Please specify "safety circuit".

Don´t give informations piece by piece.

Klaus

 

[barry]

1m, 1A, 100ma, 5ma, 'safety circuit', voltmeter. Sir, you are all over the place. Figure out what it is you exactly need, and THEN post it. Otherwise, all you are doing is annoying the people trying to help you.

 

[thannara123]

1m, 1A, 100ma, 5ma, 'safety circuit', voltmeter. Sir, you are all over the place. Figure out what it is you exactly need, and THEN post it. Otherwise, all you are doing is annoying the people trying to help you.

sorry but I already mentioned Upto 1 AMP in my first post.

safety circuit meant that some of cheap transformer less power supply which use some capacitor resistors directly,there is no isolation ,Any live touching it may be danger . (sorry for my bad english)

 

[Kajunbee]

As already suggested multiple times you can use and AC transformer to provide you isolation from the ac mains voltage. You already know what your voltage and current requirements are. So you need to shop around for a 230 volt to 6 volt transformer that can deliver about 1 amp of current. After you get the transformer then you can implement other techniques to limit the current or provide protection to devices you attach to it. If 5 ma limit is what you need then someone will be able to suggest ways to accomplish it.

 

[betwixt]

Points to bear in mind:

1. if your voltmeter is connected to almost any other circuit and you use a transformerless supply, that circuit will itself become 'live' and dangerous to touch. If that circuit has any connection to other power sources or to ground, it will almost certainly be damaged. Transformerless supplies do not break the connection between live AC and their output wires! You have been warned!

2. Capacitive dropper circuits use the reactance (Xc) of a capacitor in the same way as a resistance is used in a DC circuit. The voltage dropped across the capacitor is proportional to the current flowing through it. If you choose a value that gives say 6V out at 100mA load, it may produce 200V out at a lower current. There is no regulation in a capacitive dropper circuit and the voltage with no load can be as much as the AC you feed in to it.

A transformer is cheap, and safe. It DOES provide a safety barrier between the incoming AC and the output and it also drops the voltage so it is nearer what you need to power the meter. Power transformers have a rating in "VA" (Volt Amps) which is similar to power in Watts. If you need 6V at 100mA, the VA required is (6 * 0.1) = 0.6VA so even a very small one rated at 1VA would be big enough. You can use any VA rating higher than needed but the transformer gets bigger and more expensive as the VA rating increases.

Brian.