HOW TO TEST ICs Chips VOLTAGE REGULATOR 78XX 79XX series 7805 7815 7815 test integrated circuit

HOW   TO   TEST   ICs   Chips   VOLTAGE   REGULATOR

IC   VOLTAGE    REGULATOR    TESTING   /   test  integrated   circuit  


test  integrated   circuit    TEST   VOLTAGE  REGULATOR
                                  

IC regulator   LM317T  7915CT   L7809CV
                                 IC  Regulator   LM317T   7915CT   and   L7809CV on  PCB



IC  Voltage  Regulator  part number  78XX  79XX series  are  popular ICs that  use  on  many power supply circuit.   Regulate voltage function  is  necessary  for every  electronic circuits so we always find these ICs   on  many circuits  ,  The  ICs  is  small and has  many package to choose.    The basic  package is  TO-220 and  TO-3  as  shown on   photo below.   78XX series is  for positive output   for part number  example   7805 =  5VDC    ,  7812 = 12VDC  ,  7815 =  15VDC etc.   79XX series is  for  negative  output  for  part number  example 7 905 = - 5VDC    ,  7912 =  -12VDC  ,  7915 =  -15VDC etc.   The part number has  L  at  the middle like 78L05  , 78L12 , 78L15 means  it  has  output  current    around 100mA   and  part number  has T at end  like  7805T , 7812T , 7815T
mean it  has  output  current    around  1A.    Every  electronic  learner  can  check  good or  bad  ICs so he can repair circuit.   Before checking   the ICs , you need to know it's  pinning  function .  78XX series and  79XX series  has different  pinning arrangement.    If  you are working with circuit repairing ,  It  is  good  that   you  can  remember   the  pinning  as  shown   below.


VOLTAGE REGULATOR     7805 7815  7815
                                      This   package   is   TO-220    (  TO = Transistor Outline ).




VOLTAGE REGULATOR
This package   is   TO-3



VOLTAGE REGULATOR
                                This package is  TO-92  style.



For  78XX series ICs  ,   pin  number  1   is  input , Pin number 2  is    Ground   and Pin Number 3 is  Output.    If   you   can   not remember that   information   , you can  check  it  with  datasheet.   If  you  do  that  pinning  checking  for  2 or  more times  then  you  will automatically remember. 
                                                  Front View  for  78XX  series   terminals.



For  79XX series ICs (  front View )  ,  pin  number  1   is   Ground  ,  pin number 2 is  input  and  Pin number 3  is   output .

Front View  for  79XX  series   terminals.





VOLTAGE REGULATOR

ICs  Chips  VOLTAGE REGULATOR



For  TO-92    78XX  series ICs.  (  front view )   you  may  focus  on   its pinning  as show on  arrangement  it   is different   from   from TO-220  package.   I   have checked   it for many time and  If  you   have  time , you can research   pinning of  TO-92 and   TO-220  to  compare pinning arrangement.



How to check electronic device
-------------------------------------------------------------------------------

How to test  SCR 

How to  test  TRIAC 

How to test  Mosfet

Choose   these   articles   to  read   more  about  device  testing.


------------------------------------------------

On  photo , It is  a  7815CT  which is  a good condition.
Input and ground  has  high  input resistance range   Mega Ohm.
Output and ground  has  high  input resistance range Kilo  Ohm.


Test a Voltage Regulator  7815CT  ground and input
                                  Test  input and  ground  terminal   of  7815CT
                      

Test a Voltage Regulator  7815CT  ground and output
                      
 Test  output and  ground  terminal   of   7815CT


On  photo , It is  a  LM317T  which is  a good condition.
Adjust  and output   has  high  input resistance range   Kilo   Ohm.
Adjust  and input    has  high  input resistance range    Mega  Ohm.

                                Adjust  and output  has resistance range Kilo Ohm.


วัดไอซี  IC regulator  LM317T
                                 Adjust  and input  has resistance range Mega  Ohm.
                              



Step  to   check    IC  Voltage Regulator.
It    is  divided   into    2    method.

1)  On  board testing .........find part number on  ICs  for example  78L05  voltage output must be 5VDC  ,   78L12  output voltage  must be 12VDC  , then you can use VDC test function on multimeter to check  that output voltage  if  it  has output as rated specs  means those  ICs is  still good.   In  case  of  input of ICs  is  normally present , but  no output voltage ,  you have to switch off circuit and remove the ICs from PCB to check it as off-board testing.

2.   Off  board testing ......after removing  the ICs  from  PCB  then  set  multimeter to resistance test function.,  connect test leads  then  measure to read  resistance value.

2.1   Measure  Input   and   Ground   then   switch  the test leads   as photo and  do testing again.

Test  VOLTAGE REGULATOR     7805 7815  7815
Input   and   Ground  terminal  testing   , the first measurement.
Good  ICs    has   l
ow  resistance    value  1  time.


TEST  ICs  Chips  VOLTAGE REGULATOR
  Input   and   Ground terminal testing   , the second  measurement ( switch test leads)  Good  ICs   has high resistance  value  1  time.



2.2   Measure  Output   and   Ground   then  switch the test leads   as photo and do testing again.

Test  VOLTAGE REGULATOR     7805 7815  7815
Output   and   Ground  terminal  testing   , the first measurement.




Test  VOLTAGE REGULATOR     7805 7815  7815
Output   and   Ground terminal testing   , the second  measurement ( switch test leads)



Check  measurement  results of  Input   and   Ground  terminal  testing  with  these   criteria.
Good  ICs ....the first  testing  and the second testing  ( switch test leads )
the measured resistance value  get  result as
 -  High resistance  value  1 time.
 -  Low resistance  value  1 time.

Bad  ICs  (short circuit)....get very low resistance ( almost  be  0 ohm ) for the first and the  second testing.
Bad  ICs  ( leak )....get very high resistance for both testing ( almost the same value and  high  resistance value ).

Check  measurement  results  of     Output   and   Ground  
with  these   criteria.
Good  ICs ....the first testing  and the second testing  ( switch test leads  ) resistance value  get  result as
 -  High resistance  1 time
-   Low resistance   1 time.

Bad  ICs  (short circuit)....get very low resistance ( almost  be  0 ohm ) for the first and the  second testing.
Bad  ICs  ( leak )....get very high resistance for both testing ( almost the same value and  very  high  resistance value ).