Showing posts with label How to check electronic device. Show all posts

Tuesday, November 30, 2021

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 VOLTAGE REGULATOR TESTING

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

OPTO COUPLER TESTING

Optocoupler is one type of ICs , It isolates input and output section by using optical technology this feature increase safety of circuit. Optocoupler has many part number , different part number has different output type so before checking it has to use part number to research with datasheet and find input type and output type. How to check Optocoupler it depends on device type inside the ICs. There are many package of Optocoupler , briefly , through hole and SMD. For through hole type such as DIP-6 which has 6 pin DIP-4 which has 4 pin etc.

Optocoupler MCT2E DIP-6 Package

I will use MCT2E for example testing. After researching with datasheet we know input is LED
terminal number . 1 is Anode and terminal number 2 is cathode , this case , we will check it by using the same method as LED checking. The dot on ICs body mean that the first pin start from that. The output is a transistor pin number 6 is Base terminal , pin number 5 is Collector terminal and pin number 4 is Emitter terminal , so checking method it has the same method as transistor checking.

Step to test Optocoupler.
1. Input Checking.

Test LED with Digital and analog multimeter

test led with multimeter

LED TESTING
LED is a kind of diode and it is a basic electronic device on circuit so it's good to know how to check LED good or bad. The common size available on the market is 3mm 5mm and 10mm Dia which is popular type and other size and style are produced too but it use with some equipment. . Before checking LED , it need to know the most important information
1). Specification of LED 2) Test Function of multimeter to check LED.
After learning these 2 points then we can move to step to LED checking.

LED size and color

1). Specification of LED.
Led is a low current consumption device. Don't let too much current flow through it when using at circuit it always need limiting current resistor to decrease the current. Limiting resistor calculation will be discussed when make a circuit design. Generally small led need current around 10-25mA and big led around 20-50mA so when check it by analog multimeter use the proper current range to check it and don't hold the test lead for a long minute , we will describe on the next section.

HOW TO TEST DIODE by digital multimeter and Analog multimeter

HOW TO TEST DIODE

DIODE TESTING
Diode is a basic electronic device and it has wide application on many circuit such as rectifying , switching , protection circuit , polarity protection etc. Before checking it need to know a necessary information about diode. Diode has many package below is some example. On its body has shown diode symbol so that you can know its terminal function anode or cathode.

This is a symbol of diode , Anode for positive voltage ( + ) and Cathode for negative voltage. If supplying the right polarity voltage to the diode terminal ... V+ to anode and V- to cathode this called " Forward Bias " this case diode will let current flow. If supplying reverse polarity to the diode ..... V- to Anode terminal and + to Cathode terminal , this case diode will block current and no current flow this called reverse bias. In case of reverse bias there is only leakage current flow and amount as uA or mA for Germanium Diode and there is not any leakage current for Silicon Diode.

Example of Diode Package

Diode symbol

DO package ( DO = Diode outline )

Stud package it has screw and nut to tighten the wiring connection.

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.

Leads arrangement of BRIDGE RECTIFIER DIODE

HOW TO TEST TRANSFORMER with Multimeter

TRANSFORMER TESTING Transformer consists of 2 winding ; primary winding and secondary winding. Transformer is the important device on power supply circuit. It convert high voltage to low voltage and provide safety feature as isolation between input and output , Isolation between high AC voltage and low AC voltage can achieve by transformer. This article explain basic transformer testing.

Step to test transformer with Digital Multimeter.
1. Turn equipment off ( unplug ) or remove power source from transformer under test.
2. Turn rotary switch to resistor test function.
3. Connect test leads to primary winding.
Good transformer get measured resistance value.
Bad transformer ( open winding ) meter display " OL "
Bad transformer ( short turns ) meter display 0 ohm or very much low resistance.
4. Connect test leads to secondary winding.
Good transformer get measured resistance value.
Bad transformer ( open winding ) the meter display " OL "
Bad transformer ( short turns ) meter display very much low resistance.

Test primary winding , display resistance value.

Bad transformer display " OL" (for open ).

Bad transformer display very much low resistance (for short ).

HOW TO TEST TRANSFORMER with Digital Multimeter

Test secondary winding ,display resistance value.
Bad transformer display " OL" (for open ).
Bad transformer display very much low resistance (for short ).

5. Test transformer core with primary winding. ( Isolation testing)
Connect test leads to transformer core and primary winding.
Good transformer meter display " OL "
Bad transformer meter display some resistance (leak)
6. Test transformer core with secondary winding. ( Isolation testing)
Connect test lead to transformer core and secondary winding.
Good transformer meter display " OL "
Bad transformer meter display some resistance (leak).

Test transformer core with primary winding ( isolation testing).
Good transformer meter display "OL"
Bad transformer (leak) meter display some resistance value.

Test transformer core with secondary winding ( isolation testing).

Good transformer meter display "OL"

Bad transformer (leak) meter display some resistance value.

7. Test isolation between primary winding and secondary winding.
Connect test leads to primary winding and secondary winding.
Good transformer meter display " OL ".
Bad transformer (leak) meter display some resistance.

Test isolation between primary winding and secondary winding.
Good transformer meter display "OL"
Bad transformer (leak) meter display some resistance value.

Step to test transformer with Analog Multimeter.
1. Turn equipment off ( unplug ) or remove power source from transformer under test.
2. Turn rotary switch to resistor test function , Rx1 range.
3. Connect test leads to primary winding.
Good transformer get measured resistance value.
Bad transformer ( open winding ) the pointer point at " ∞ ".
Bad transformer ( short turns ) the pointer point at 0 ohm.
4. Connect test leads to secondary winding.
Good transformer get measured resistance value.
Bad transformer ( open winding ) the pointer point at " ∞ ".
Bad transformer ( short turns ) the pointer point at 0 ohm.

Test primary winding, use Rx1 range ,
meter display some resistor for good transformer.

Test secondary winding, use Rx1 range ,

meter display some resistor for good transformer.

5. Test transformer core with primary winding. ( Isolation testing).
Turn rotary switch to Rx10K range test function.
Connect test lead to transformer core and primary winding.
Good transformer the pointer point at " ∞ ".
Bad transformer (leak) the pointer show some resistance value.
6. Test transformer core with secondary winding. ( Isolation testing).
Connect test lead to transformer core and secondary winding.
Good transformer the pointer point at " ∞ ".
Bad transformer (leak) , the pointer point at some resistance value on scale.

Test transformer core with primary winding ( Isolation testing ).
Good transformer , the pointer must point at " ∞ ".

Test transformer core with secondary winding ( Isolation testing ).
Good transformer , the pointer must point at " ∞ ".

7. Test isolation between primary winding and secondary winding.
Connect test leads to primary winding and secondary winding.
Good transformer , the pointer point at " ∞ ".
Bad transformer , the pointer point at some resistance value on scale.

How to check electronic device

Multimeter test capacitor and how to test electronic components

HOW TO TEST CAPACITOR

CAPACITOR TESTING. This article will explain both capacitor testing using digital multimeter and analog mulimeter.

Step to test capacitor with digital multimeter
1. Remove power from circuit by switching equipment off / unplug. the capacitor under test must no voltage present.
2. Discharge capacitor before testing , failture to do this will case damage to meter and electric shock.
Researching how to discharge capacitor is essential too.
3. Don't touch metal tip of test leads during testing.
4. Insert black test lead to COM- jack and red test lead to VΩ jack.
5. Turn rotary switch to capacitor range / capacitor test function. The display will present capacitor symbol.
6. Connect the test lead to capacitor under test terminals.
7. The display will present some capacitor value.
Good capacitor will show value as printed on its body ( the closest value is still good capacitor ).
Bad capacitor ( degrade ) show capacitance value much lower from it original value.
Bad capacitor ( open ) will not show any capacitance value.
Bad capacitor ( short ) will not show any capacitance value or show " OL"

Step to test capacitor with Analog multimeter.
1. Remove power from circuit by switching equipment off / unplug. The capacitor under test must no voltage present.
2. Discharge capacitor before testing , failure to do this will cause damage to meter and electric shock.
3. Don't touch metal tip of test leads during testing.
4. Insert black test lead to COM- jack and red test lead to P + jack.
5. Turn rotary switch to resistance range / resistance test Function.
Capacitance value around 10uF use Rx1K range.
Capacitance value around 47uF use Rx100 range.
Capacitor value around 470uF - 2200uF use Rx10 range.
Capacitor value around 2200uF up use Rx1 range.
6. Test 2 time , connect test leads to capacitor terminals and switch test leads and do testing again. The meter will present result as below.
Good capacitor , the pointer will move forwarding to 0 ohm side then move backward to ∞ .
Bad capacitor (open) , the pointer does not present any movement.
Bad capacitor (short ) , the pointer move forward to 0 ohm side and keep position around 0 ohm.
Bad capacitor ( leak ) , the pointer will move forward to 0 ohm side then move backward to ∞ but it does not reach ∞ position. ( The pointer still point at some resistance , not at ∞ position as a good capacitor ).

Test capacitor with Analog multimeter , 220uF use Rx100 range.

HOW TO TEST SWITCH Toggle switch Rocker switch Limit Switch

HOW TO TEST SWITCH

All kind of switch has mechanical contacts. The most basic of contacts is NC type contact ( Normally Close ) and NO type contact ( Normally open ). Some switch has only 1 NC contact , some switch has only 1 NO contact , and some model consist of many contacts ; NO NC Common terminals. The circuit diagram of switch has printed on its body. How to check switch it depends on contact type of witch.

NC type contact ( Normally Close ) , Terminal 1 and 2 is connected

NO type contact ( Normally open ) Terminal 1 and 2 is not connected

Basic output contact form consists of NC and NO contact

Step to check switch

1. Turn rotary switch to continuity test function of digital multimeter.
2 Connect test leads to the NC contact of switch. The meter will beep if it is a good NC contact. Bad NC contact , the meter does not beep. After that change switch position by pressing to ON and OFF. The good contacts will change status from ON to OFF or OFF to ON.
3. Connect the test leads to the NO contact. The meter will not beep if it is a good NO contact. Bad NO contact , the meter will beep ( short circuit).
After that change switch position by pressing to ON and OFF. The good contact will change status from OFF to ON and ON to OFF. These changing of contact represent results on multimeter display.
4. Test every NO and NC contact set. If there is only 1 contact is bad , the switch is not good.
then find the replacement.

Test NC contact of switch , the meter will beep if it is a good NC contact.
Bad NC contact , the meter will not beep.

Then change the toggle position , the NC contact connection will change too, from beep to OL.

Test NC contact of switch , the meter will beep if it is a good NC contact.

Test NC contact of switch , After changing switch position the internal contacts of switch will change too , from connected to disconnect.
Represent as beep for connected and OL display for disconnected.

30 electronic device testing.

Choose articles below to read .

1) 30 testing of electronic devices

2) Test Triac with multimeter

3) Test SCR with multimeter

4) Test MOSFET with multimeter

Multimeter test relay

HOW TO TEST RELAY with digital multimeter

HOW TO TEST RELAY

RELAY TESTING. There are may model of relay and some model has many terminals. The terminal of relay is divided into 2 section ; Section 1 is coil , for supplying voltage to control to operate as switch ON or OFF. The coil of relay has some resistance so good coil will show some resistance when testing with ohmmeter. Section 2 is output contacts which consists of NC type contacts ( Normally Close ) and NO type contacts ( Normally open ).

NC type contact ( Normally Close ) , Terminal 1 and 2 is connected

NO type contact ( Normally open ) Terminal 1 and 2 is not connected

Basic output contacts form consist of NC and NO contact.

Step to check relay.
As you have learned from above there are to type of basic circuit of contacts , connected and open. So we will use continuity test function of digital multimer to test the contact ; connected contacts must be connected as it be and open contacts must be disconnected.
1. Switch off or unplug circuit that want to test. Make sure there is not any voltage supply to relay before testing.
2. Find circuit diagram that printed on relay then find where is the coil terminals.
3. Test coil terminals , find coil terminal of relay and connect test leads to it. On the sample terminal 13 and 14 is coil terminals of relay.
4. Turn rotary switch to resistance test function.
5. Good coil present some resistance value when measuring , but bad coil of relay display
" OL " ( open circuit )
6. Test NO and NC contacts of relay , check all set of contacts.
7. Set digital multimeter to continuity test function.
8. Connect test leads to the NC contact. The meter will beep if it is a good NC contact.
Bad NC contact , the meter does not beep.
9. Connect the test leads to the NO contact. The meter will not beep if it is a good NO contact. Bad NO contact , the meter will beep ( short).
10. Test every NO and NC contact set. If there is 1 contact is bad , the relay is not good.
then find the replacement.

Find circuit diagram of relay under test that printed on relay's body.

Test coil terminals no. 13 and 14.
Good coil must present some measured resistance value.

Test NC contact this example is terminals No. 10 and No. 2.
Connect test leads to the NC contact. The meter will beep if it is a good NC contact.

Test NO contact this example is terminals No. 10 and No. 6.
Connect test leads to the NO contact. The meter will not beep if it is a good NO contact.

HOW TO IDENTIFY SILICON DIODE or SCHOTTKY DIODE ?

HOW TO IDENTIFY SILICON DIODE or SCHOTTKY DIODE

Silicon Diode is the most common use but for some circuit it need a schottky diode . Schottky diode has low voltage drop and fast recovery time so it can operate with high frequency application. We know voltage drop across Silicon Diode is 0.5-0.8V and 0.1V - 0.45V for schottky diode. I have sample of both 1N5402 standard general purpose Silicon Diode , 1N5820 for schottky diode. I will measure it and present the result on this article.

1. Silicon Diode Checking.
The voltage drop across a Silicon Diode is 0.5-0.8V and on photo = 0.528V

HOW TO TEST ZENER DIODE by digital multimeter and Analog multimeter

ZENER DIODE TESTING

ZENER DIODE TESTING Zener diode is a subtype of a diode and it use on circuit as a different function from standard diode. Standard diode we use it as forward bias mode but for Zener diode we use it as reverse bias mode on circuit. When applying forward bias to zener diode it will conduct and let current flow as standard diode , another condition when applying reverse bias to zener diode it will not let current flow until the voltage supply is over the zener breakdown voltage then it will let current flow.

ZENER

Basic Circuit of zener Diode

How to check zener diode , it has more detail then checking standard diode as it is a subtype of diode so in some condition checking method is as same as standard diode. Before checking you have to know important technical detail of multimeter. We set analog multimeter to range Rx1 or Rx10 , let consider at the test lead there is 3VDC 150mA for Rx1 range and 3VDC 15mA for Rx10.

There is 3VDC 150mA at the test leads , Rx1 range, of Analog Multimeter.

POTENTIOMETER ( small) and RHEOSTAT ( big )

Potentiometer is a variable resistor . It use to adjust signal and low current on electronics circuit. It has 3 terminals. If you want a variable resistor that can handle more current, you may looking for rheostat.

Potentiometer

Rheostat

We will name as terminal 1 and 2 and 3 when measure .

Step to check Potentiometer and rheostat.
1. Read the resistance value that marks on potentiometer or rheostat.

Multimeter test Resistor testing electronic components with multimeter

HOW TO TEST RESISTOR with Digital Multimeter and Analog Multimeter

RESISTOR TESTING Resistor is a basic electronic components. We have to test it when design circuit and repair equipment.

Step to measure resistor by Digital Multimeter
1. Turn power off or remove power from circuit under test. Failure to do this will cause damage to multimeter and electric shock.
2. During testing , do not touch the tip of test leads.
3. Insert black test lead to COM- jack and red test lead to VΩ jack.
4. Turn rotary switch to resistance range / resistance test function.
5. Connect the test leads to resistor under test terminals.
6. The display will show some resistance value.
Good resistor should show measured value that is close to its specification value.
Bad resistor ( open ) show "OL" ( over range ) on meter' display.
Bad resistor ( Degrade , resistance value is much increasing or decreasing ) get measured value that is much different from its original value.

0.5K ohm resistor and meter show measured value 0.491K ohm
so this is the good resistor.

Step to measure resistor by Analog Multimeter
1. Turn power off or remove power from circuit under test. Failure to do this will cause damage to multimeter and electric shock.
2. Never touch the tip of test leads while testing.
3. Plug the black test lead to - COM N jack and red test lead to + P jack.
4. Conduct 0 ohm adjustment the test leads and every time that change resistance ranges must make 0 ohm adjustment by this multimeter will provide the accurate resistance testing.
4. Turn rotary switch to resistance x 1K range ( and read 7. about select Rx )
5. Connect the test lead to resistor under test terminals.
6. Read resistance value from Ω scale
7. The good resistance ranges setting , make the pointer point in the area that easy to read scale. ( Rx1 Rx10 Rx100 Rx1K Rx10 setting )

1K range setting is not suitable for 270K ohm as the pointer point at around the edge of scale

Easy to read scale the pointer should point around this area on photo , not at the edge.

Better and suitable resistance range setting for 270K ohm is Rx 10K.
Notice the pointer point at the easy to read scale.

Good resistor should get the measured value that is closest to its specification value.
Bad resistor ( open ) will always point at ∞ resistance scale.
Bad resistor ( Degrade ,resistance value is much increasing or decreasing ) get the measured value that is much different from its original value.

30 Multimeter use how to test electronic device with a multimeter

Tuesday, November 30, 2021