Tecfornewbie: 2012

Tuesday, January 31, 2012

(BJT) - TRANSISTER Tuturial

I t Is t h e e l e c t r o n i c d e v i c e i n w h i c h s m a l l c h a n g e i n t h e e l e c t r i c a l s i g n a l c a u s e s l a r g e c u r r e n t t o f l o w t h r o u g h c o m p o n e n t s . I t i s t h e t h r e e t e r m i n a l d e v i c e n a m e a s

B A S E , E M M I T T E R & C O L L E C T O R .

T h e c u r r e n t f l o w i n t h e t r a n s i s t o r f r o m C O L L E C T O R t o E M I T T E R , a n d B A S E t e r m i n a l i s p l a c e d b e t w e e n t w o t e r m i n a l . A f u n c t i o n o f b a s e t e r m i n a l i s u s e d t o

R e g u l a t e t h e c u r r e n t f r o m C O L L E C T O R t o E M I T T E R .

I f t h e r e i s s m a l l c h a n g e i n b a s e c u r r e n t t h a t c a u s e s l a r g e c h a n g e i n c o l l e c t o r - e m i t t e r j u n c t i o n , a c c o r d i n g t o t h e b a s e c u r r e n t a p p l i e d t o t h e j u n c t i o n t h e c u r r e n t f r o m

M a i n j u n c t i o n [ c o l l e c t o r - e m i t t e r ] i n c r e a s e o r d e c r e a s e d e p e n d u p o n t h e b a s e v o l t a g e .

T h e r e a r e t w o t y p e s o f t r a n s i s t e r ,

P n p

Np n

I n p n p t y p e t r a n s i s t o r s t h e c u r r e n t i s d i r e c t e d t o w a r d s b a s e a n d i t i s f o r m e d w i t h h i g h l y d o p e d P - R E G I O N a n d l i g h t l y d o p e d N - R E G I O N .

When u apply ground (o volts) to the base the transister gets ON.

I n n p n t y p e t r a n s i s t o r s t h e c u r r e n t i s o u t w a r d s f r o m b a s e a n d i t i s f o r m e d w i t h h i g h l y d o p e d N - R E G I O N a n d l i g h t l y d o p e d P - R E G I O N .

similarly,

When u apply +V volatge to the base the transister gets ON.

l e t u s c o n n e c t t h e t r a n s i s t o r s a s s h o w n i n i m a g e b e l o w .

v o l t a g e s o u r c e o f 1 v o l t o f p o s i t i v e t e r m i n a l o f t h e b a t t e r y i s c o n n e c t e d t o t h e b a s e t e r m i n a l w i t h r e s p e c t t o s o u r c e .

e m i t t e r t e r m i n a l a n d o t h e r s i d e i s c o n n e c t e d t o c o l l e c t o r .

A s w i t c h i s c o n n e c t e d b e t w e e n b a s e t e r m i n a l a n d v o l t a g e s o u r c e .

W h e n s w i t c h t u r n O N , v e r y s m a l l v o l t a g e a r o u n d 1 v o l t a g e a p p l i e d t o t h e b a s e t e r m i n a l , t h e s e l e a d t o t u r n o n t h e t r a n s i s t o r , h e n c e c u r r e n t f l o w t h r o u g h t h e

E m i t t e r - t o - c o l l e c t o r .

T r a n s i s t o r i s t u r n o n u n t i l b a s e v o l t a g e i s a p p l i e d , i f t h e b a s e v o l t a g e i s d i s c o n n e c t e d t h e t r a n s i s t o r g e t t u r n o f f .

W h e n t h e b a s e v o l t a g e v a r i e s t h e r e i s l a r g e c h a n g e i n e m i t t e r - t o - c o l l e c t o r t e r m i n a l , s m a l l c h a n g e i n b a s e v o l t a g e c a u s e s l a r g e c h a n g e i n e m i t t e r - t o - c o l l e c t o r

V o l t a g e , t h e s e b e h a v i o r o f t r a n s i s t o r m a k e t r a n s i s t o r m o s t u s e f u l c o m p o n e n t i n a m p l i f i c a t i o n , a s a n A M P L I F I E R .

Saturday, January 14, 2012

8051 ISP Programmer for NXP design tuturial!!

Hi guys,

Today I m going to show you the basic concept of ISP programmer and how you can actually make this circuit into your own.

Most of the newbie’s are searching for proper schematic and concept but let me tell you one thing most of the schematic are wrong the reason they do is. if they provide proper schematic anyone can make very easily so they interchanged some connection in the schematic I came to know all this while doing lots of research for programmer. I made this blog for all hobby guy and one who actually want to do something in embedded with 100% genuine information’s.

The most easy programmer can be made with NXP microcontroller it doesn’t required any extra pins so I m using NXP.

Let’s start,

To transfer the program into microcontroller we need to connect two pins of microcontroller one is TRX and other is RDX and RESET pin for making it into ISP mode. when reset is kept high for atleast two machine cycle it goes on ISP mode and program transfer into chip.

And max232 ic which act as a bridge between computer and microcontroller , you must be asking why we need this IC? The answer is we are communicating with computer, the computer has high voltage level more than 5v , it produce high voltage binary bits of information this voltage level would be very high because microcontroller has maximum voltage is 5v , so it take the high voltage bit and convert into lower voltage so microcontroller can understand this information’s. that’s all we need in programmer part.

this circuit will design in under 9$ !!!

Parts list

· Max232cpe

· P89v52rd2(8051 Philips)

· 16pin ic socket

· 40 pin ic socket or ziff socket

· 5-- 1uf capacitor (electrolyte or ceramic both works) it is needed for coupling capacitor in max232 ic

· 1-- 10uf capacitor

· Copper clad sheet size (100m*150mm)

· 4--screw channel each of 8pin or you can buy in a pair and fix to make it 8pins on each port and 1---pair for vcc n gnd.(1 pair means 2screw in 1set)

· PCB etching solutions ferric chloride available at any electronic shop.

· 8—10k resister of ¼ watt for pull-up resister

· 1—8.2k resister of ¼ watt for reset

· 2—1k resister of ¼ watt for led’s

· 2-- led of 2mm size pick any two color of our choice 3volts.

· 1-LM7805 voltage regulator 5volts needed for circuit and avoid overvoltage and damage.

· 1-Dc jack

· 1—push button &push button cap

· 11.0592 mhz crystal

· 2---22pf ceramic capacitor

· 1—DB9 connector

Your done with parts lets make it working!!

click here for large :

Now we have schematic now design in pcb designing software like eagle you will get PCB layout of that schematic like this,

And top layer will look like this,

Print this layout in glossy paper and transfer the design in pcb board using toner transfer method you can search on internet about this you will get all the information how to do that.

When the board is design make the drill in all points where components need to be attached and be carefull the tracks are two small n they are very near to each other avoid short while soldering the components.

IMPORTANT NOTE:

While designing the circuit in (eagle) I made a connection but its turns out to be in opposite polarity , so dc jack positive point become negative and negative point positive so first check your adaptor pin polarity before turning on the circuit.

How you check your adaptor is in right polarity or not??

Answer: take the multimeter the test in following points,