looking for voltage regulator IC

[punakawan69]

i think i will take life insurance first before doing that...LOL...

this is for my final project in my college..hope it'll works...chased ny deadline...thx evryones!

 

[Hero999]

It's not so much isolation from mains voltage that's the problem, it's that there no current limitation without an isolation transformer. If the primary capacitor fails short circuit you're going to have a ball of plasma on your hands.

Use a self healing film capacitor that can handle 2kV spikes and that should never happen.

 

[Sceadwian]

That assuming the person making the circuits knows that though Hero. Bad thing to assume with people making circuits on the Internet. Space Varmint was planning on using a non-isolated supply and wanted to use a tantalum capacitor.

 

[punakawan69]

acordng to the speakerguy's scheme, for the resistor...which watt will we use? is it enough if we use 25 W??

 

[Speakerguy]

You need to simulate the schematic above and determine what values you need for the series R and the capacitor. Then calculate power. But 25W will be huge, way larger than you need. If you need 100ma then (0.1A)^2 * 100R = 1W so you should use a 2W or larger on the safe side. More importantly you need to make sure the resistor has a working voltage greater than your line voltage. This is easy in 120VAC countries, but might be a concern in 240VAC countries.

That schematic is just one I pulled off the net. It's good for 20ma. If you want 100ma you need to change the main cap to 5uF and the filter capacitor needs to increase to 3300uF or more, depending on how clean you need the voltage.

 

[punakawan69]

well, i need the 5 VDC output to be connected to microcontroller. I'm using ATTINY90s2313. So, i think i just need small current. 20ma is good enough,am i right?

umm.. i need all of this, to make a current sensor which detect 220VAC.and will be sent to ucontroller.and the ucontroller need 5 VDC input.... but of course,i want it transformless...

do u have any better idea?
anyway.. thx so much mr.speakerguy...

 

[blueroomelectronics]

Why is transformerless so important?

What will the microcontroller be doing?

 

[punakawan69]

Why is transformerless so important?

What will the microcontroller be doing?

well..this is my opinions:
1. transformer is need a bigger space.
2. more expensive
3. heavy
4. i think its outofdate...hehehehe...

What the ucontroller will be doing?
1. it will detect if there is a current or not (in my current sensor). If there is a current or 5VDC input, then the microcontroller will sending data to LCD(for example,which is connected to it) that the device is ON state.
2. But if there's no current or input, ucontroller will sending data to LCD that the device is OFF.
3. But we must programming the micro first...

 

[Sceadwian]

Transformers are not out of date and never will be, or just about every power supply you've ever touched wouldn't have one in it.

 

[punakawan69]

Thx to speaker guy... it worked!! i did it... the output become 4,7VDC..(i used 4,7 zener.)

double thumbs 4 u!!

 

[Speakerguy]

Good to hear. Just be careful with it since it's not an isolated supply.

 

[Hero999]

You need to simulate the schematic above and determine what values you need for the series R and the capacitor. Then calculate power. But 25W will be huge, way larger than you need. If you need 100ma then (0.1A)^2 * 100R = 1W so you should use a 2W or larger on the safe side. More importantly you need to make sure the resistor has a working voltage greater than your line voltage. This is easy in 120VAC countries, but might be a concern in 240VAC countries.

That schematic is just one I pulled off the net. It's good for 20ma. If you want 100ma you need to change the main cap to 5uF and the filter capacitor needs to increase to 3300uF or more, depending on how clean you need the voltage.

Often its' much cheaper to use several resistors in series to get a higher/wattage voltage rating than buying special high voltage/power resistors.

 

[pascalmoustache]

Hi i need a datasheet or an equivalent for jcv amplifier ic vc5022

 

[Hero999]

Please create your own thread rather than spamming soneone else's with irrelevant questions.