yes, but are u allowed to use a rgulator ..or do you have to build it with individual components..?

 

oh yes yes, you mean regulators like LM317 IC and all? yes, im allowed to use them...any ideas on how can i build one with good efficiency? ops: can i get them from you?

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

williB? not that I dont want to "pay attention" while you're teaching me , but i guess i got to sleep. i will be back in...2 hours time to read ur replies.

thanks you so so so much

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

well i only have one LM317 targeted for my robot car. ops: sorry

 

the datasheet of the LM317 will give you alot of ideas for building a good regulated supply. and the LM317 is a commonly available regulator that you can find at any electronics shop

 

Thanks for that guide regarding LM317.

Would to ask how does the transformer used in switch mode power supply varies from the one used in linear regulator? I thought the selection of proper transformer depends on the transformer ration? For instance, 240:12. Won't we need the same type of transformer for both linear regulator circuitry as well as switch mode regulator circuitry as the desired output is 12V DC?

Thanks...

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

the transformer selection does depend on the ratio
as i understand it a switching powersupply somehow increases the frequency thus uses a physically smaller transformer.

 

Hi there, I've read about the implementation of transformerless AC/DC converter. Not implementing this in the project, just want to ask something this form of AC/DC converter.

It states that it is not advisable to implement such transformerless AC/DC converter to certain applications, such as a battery charging circuit, where a user can easily have direct contact with the 240V AC supply, which is dangerous.

Would like to ask about the term "direct contact" used in here.

Just curious that certain house appliances that we're using has direct contact to the 240V AC supply as well. We do know that it is dangerous and we need to be aware of it and becareful while using them.

Does this mean that it is also practical to implement an transformerless AC/DC converter for a battery charging circuit, where the circuit is being "stored" in a proper casing?

Sorry for my nonsense again...

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

Does this mean that...I'm not sure the available transformers in the market, so for example:

Ratio of 240:24 at 60Hz is a bigger than 240:24 at 120Hz?

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

The ratio is the same, but the transformer can be physically smaller - although 60Hz to 120Hz isn't enough of a change to make much difference.

A switch mode supply normally will work in KHz, sometimes in the 100KHz range, this reduces the transformer to about 10% of it's 50/60Hz size.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

the microchip site has a transformerless powersupply design ,but it is anly good for a few mA..that the PICs use..
did u order your PIC ?

 

Thanks, I will read up more from there.

About the PIC microcontroller, I can only get them this Friday as my class ends late today and late as well for tomorrow. Thursday is a public holiday here. I'll be getting a unit of 16F648A and a unit of 16F628. Thanks...

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

you are going to need to get a programer , or make one --find a nice parallel programer..

 

As shown is the circuit I intend to use for my one of my charging circuitry for the battery where the source is from a solar panel.

The input of this circuit, the solar panel, will not be the one seen or tested earlier, which is one with low output current.

Would like to ask the following questions:

a.) How do I determine the appropriate value of the capacitor as well as the inductor? Can I use approximately 10 microFarad for the capacitor? As for the inductor, is approximately 100 miliHenry an appropriate value?

b.) Issit advisable to include a zener diode in parallel with the Load as well as the capacitor?

c.) Should I boost to a voltage level of 15V for charging purposes in this circuit?

d.) With an approximate current value of 40mA, power output of 0.3W, voltage output of 7.5V, can this circuit be operated?

Need advice...Thanks a lot...

Sorry for not including the arrows to denote the flow of current...

Attached Images

boost_converter.jpg (21.3 KB, 278 views)

__________________
Lord Robert Stephenson Smith Baden Powell\'s last message : -BE PREPARED-

 

what is the "clock pulse" ??
if it a switch .. why not just use a switch..???

Attached Images

c1.jpg (11.3 KB, 236 views)