Yes, we all know that. But you are preparing to lose your life, how strange?

Unless all components are mounted in an insulated box, with no possiblity of touching anything which is electrically connected to the circuit, this is a VERY BAD idea.

The simple solution can resulting in you speaking to your god sooner than you expected.

JimB

im looking for a simple rectifier/filter circuit with resistors to connect ttl ICs. Im in india so its 220V@50Hz.. Im unable to use transformers as the circuit becomes bulky.. I cannot afford to burn out chips as im still a student...

buy one. Its cheaper than electrocuting yourself :shock:

this is why I only go 12V and under in all my circuits.

As already suggested - this is a SERIOUSLY BAD IDEA! - such circuits do exist, but not as general purpose power supplies, only for very specific 'one off' designs, where they are designed for that exact purpose.

Use a transformer!.

Originally Posted by samratyuvi

I understand your consern...
But i want to install digital ic's connected to thyristors that control domestic equipments... i dont know how to miniaturise my digital circuit so that it fits into wall mounted switch board..
Please help me... my project depents on this a lot..

A lot depends on exactly what you want to do, but first thing! - dump the TTL, it's too power hungry, use CMOS instead.

I don't understand why a simple wall-wart transformer can't be used for this application? What am I missing? A thyristor can be driven by DC to control AC, right?

Originally Posted by samratyuvi

Iam loking for cmos chips now... But is there any way to use the ac power directly in this chip?
:?:

You can drop the mains voltage for low current by using a series resistor or capacitor and a zener diode. Be aware that you have to make sure that components are specified for the use you put them to, particular capacitor types are used for voltage droppers in this way. If you use a resistor, you have to make sure it is high enough wattage, and that the heat can dissipate from it OK.

MicroChip (yet again!) have an application note for a light dimmer using a PIC, it uses this technique to power it.

Originally Posted by samratyuvi

I will try and play around with this circuit...

:shock: :shock: :shock:

...and if I survive through this project i will let you know the results..

It is better to have a dead circuit than a dead human.

My circuit is showing symptoms of life now.

life is a symptom :?:

BEFORE you even dare to connect ANY part of your circuit to ANY socket in the wall, go with a lower voltage first. Buy yourself an adapter that supplies 9VDC or lower, so that if by accident you connect the live wires together, the explosion will be minimized.

Anyone seen the grizwalts family christmas where chevy chase plugs in 50 gazillion or some odd strands of christmas lights, and makes his home the brightest in the city? That was so funny, the whole electric system in the city couldn't keep up.

Now if you short the live wires in your home long enough, you could end up having a similar problem.

Originally Posted by mstechca

Now if you short the live wires in your home long enough, you could end up having a similar problem.

Doesn't your home's electrical wiring use 15A fuses or circuit breakers?

Originally Posted by audioguru

Doesn't your home's electrical wiring use 15A fuses or circuit breakers?

Don't Americans use Canadian quarters instead of fuses? :lol::P:lol: