Tuesday, November 30, 2021

Multimeter test bridge rectifier diode

HOW   TO   TEST   BRIDGE   RECTIFIER   DIODE   


HOW TO  TEST  BRIDGE  RECTIFIER  DIODE
HOW TO  TEST  BRIDGE  RECTIFIER  DIODE 



HOW  TO   TEST   BRIDGE   RECTIFIER   DIODE 

Full  bridge   rectifier  diode   consists   of   4   diode  inside the package.   It   is  a  common part of power supply.   Internal  wiring for  4  diodes  shown  as   below. Although   there are many package of   Full  bridge  rectifier   diode ,  it has the same internal wiring diagram  and   4  terminals  , namely  ;   +  ,   -   AC  and   AC.
The  +  terminal  has longer lead   than the others   and   there is cut  marking  at the corner .   The sip package AC and AC leads   located   at  the  inner.  KBPC package  indicate only  2  terminal name that   is   +   and  AC ,    the others  you have to  find  ...  -   terminal  is  diagonal  to the  +  terminal and  the rest  AC terminal   is  diagonal   to   the first   AC  terminal   too.



BRIDGE  RECTIFIER  DIODE
Leads   arrangement   of    BRIDGE  RECTIFIER  DIODE  




   
BRIDGE  RECTIFIER  DIODE
SIP   package    BRIDGE   RECTIFIER   DIODE  


 
BRIDGE  RECTIFIER  DIODE
KBPC  package has quick  connect   terminals.



Shown terminal arrangement for  KBPC package.    AC terminal  is diagonal to AC terminal , also , - terminal  is diagonal to  + terminal.


BRIDGE  RECTIFIER  DIODE
BRIDGE   RECTIFIER   DIODE   TERMINAL FUNCTION 



    KBPC  package    has  wire  lead.   At   the top ,  there  is   symbol   of    terminal function  at the top
BRIDGE  RECTIFIER  DIODE




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Step   to   check   bridge   rectifier   diode.
Before checking. study this internal wiring of 4 diodes   first.   D1 and  D3  arrow head  has the same direction.   D2 and  D4    arrow head  has the same direction  too.  When   supplying  forward bias to  D1 and D3 there is some voltage drop.     1 diode has  around  0.5-0.8V voltage  drop  so  if  2  diodes ( D1 and D3 )  voltage  drop  will  be   as  0.5V  x 2 =  1V  approximately ,  or  some case  0.8Vx2 = 1.6V .    For   D2  and D4   likewise.

BRIDGE  RECTIFIER  DIODE


1.  Turn  rotary  knob  of multimeter  to  Diode  Function.
2.  Connect the test leads   as photo.   If   Diode is good ,  multimeter will display voltage drop diode around  1V.   1V  is  a  voltage drop across  2  Diode   ( 0.5Vx2).  If  there is  1 of  any didoe short , the   meter   will display around  0.5V.    If  there is any  bad  diode found  as  short or open , no need to do the next checking.


TEST  BRIDGE  RECTIFIER  DIODE
Connect   test lead   to +  and  - terminal.
Set   meter to diode test function.


TEST  BRIDGE  RECTIFIER  DIODE
Connect   test  lead   to +  and  - terminal.
There is voltage drop across diode ( 0.8-1V) =  good diode


3.  D3 testing.  connect test leads    as photo below to check the  individual diode ,  D3.
The good diode will get around  0.5V.   Short  diode will display  0.002 and  open diode  will display " OL"


TEST  BRIDGE  RECTIFIER  DIODE

 

In case of  diode is good  ,   it   will display  some  voltage drop   on example   is  0.536V
TEST     DIODE  multimetro  мультиметр




 In case of bad  diode (short)  ,  it   will display  very low voltage drop  on example   is  0.002V
TEST  BRIDGE  RECTIFIER  DIODE



  In case of  bad diode  (open)  ,  it   will display   "OL"
test    bridge   rectifier  diode


4.  D2 testing.   check the  individual diode ,  D2.  Connect test lead as photo below.
The good diode will has voltage drop around   0.5V.
For bad diode (short and open)  already described  on  above photo.


BRIDGE  RECTIFIER  DIODE

5.  D1 testing.  check the  individual diode ,  D1.   Connect test lead as photo below.
     The good diode will has voltage drop around  0.5V.
    For bad diode (short and open)  already described  on  above photo.


BRIDGE  RECTIFIER  DIODE



5.  D4 testing.  check the  individual diode ,  D4.   Connect test lead as photo below.
    The good diode will has voltage drop around  0.5V.
     For bad diode (short and open)  already described  on  above photo.

TEST  BRIDGE  RECTIFIER  DIODE


In addition when you measure  AC1  and AC2 terminal ,  it must not be as  short connection.   Terminal + and  -  it must not  be as short connection  too.  The above checking  is  off -board  checking.  If you want to do on board checking   and  use voltmeter  function  to check the output  of  full bridge   rectifier   diode  by using   this equation.
Vdc =  1.41 x Vac  if   there is  capacitor filter and resistor load.
Vdc =   0.9  x Vac    if  there is  resistor load only.


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