Capacitor

Capacitors are used to store charge Q and this charge is usefull it acts like a battery after the power supply have been removed it is also used to smooth out voltage. Capacitance is measured in fared (1 Fared is 1,000,000, mF microfared). Capacitors takes less than a second to fully charge.

Time constant
T=5RC
(R)resistor=ohms
(C)capacitance=farad
(T)time=sec

Measure charge
C=Q/V
(C)capacitance=farad
(Q)charge=coulombs
(V)voltage=V

To measure capacitance in
Series :  1/Ct=1/C1+1/C2
Parallel : Ct=C1+C2

4841 Voltage regulator

A voltage regulator is a electrical component that can regulate a higher voltage (input) into a specific voltage (out put) and maintain a constant voltage level even though the input voltage fluctuate.But the input voltage must not drop below 2v of the specify voltage of the out put eg 5v out put, the input must not drop below 7v or else the out put will start to go lower.

As seen in the above picture , this is my circuit from my AC to DC blog. I use a 7805 regulator 05 stands for the voltage its going to out put. From the bridge rectifier it has a raw voltage of 16v which is then pass through the voltage regulator and out put a steady 5V.

4841 Starter motor

Visual Inspection


Check for any sign of
- Overheating
- Burning
- Physical damage of insulation and coil winding
- Poling

Ground Circuit Tests

Test the ground by setting to ohm on your meter and poke the probebetween each of the commutator segments and the armature core or shaft. 

Continuity Circuit Test

With the Ohm meter in the same range check continuity between one of the commutator segments while moving the second probe around on each of the other commutator segments. 

Testing Commutator

Measure the Commutator diameter with a vernier caliper and check the mica undercut depth as necessary. 

Testing for internal short circuits using a growler

Alternative Method of Testing Armature
Using a 48volt test light

Continuity test

Keep one probe on one segment and move the other probe around each of other segments.The test light should glow.

Ground test

Place one probe on a commutator segment and the other on either the armature core or shaft. The test light should not glow.

Test the Field coils for Continuity
Checking for continuity in the field winding place the ohm meter probes on each end of the field winding. Result 0.01ohm


Test the Field coils for grounding
Ohm meter place the positive probe on the field wire or brush, then the common probe on the body of the starter. The meter should read Infinity.
Brushes


Brush Holder Assembly
Check for short circuit between insulated brushes and holder set the Ohms meter on the lowest resistance.  Place one of the probes on the brush and the other on the metal retaining plate 

4841 Battery testing

SAFETY: Safety glasses should be warn at all times and a nearby water supply should be available 


1. Visual Check
Check the battery case for cracks,swelling and leaks (battery need replacing if any of this 3 sign is showing).
Check electrolyte level in all cells that they are at the correct level  add distilled water if needed (using tap water will shorten lifespan of battery and DO NOT over fill).
Check battery terminals for corrosion and residue, clean if needed (wire brush)


2.O.C.V (Open Circuit Voltage) Test
Tools needed: Voltmeter
Then to remove surface charge with the car off turn the light on for 1 min (if surface charge is not remove  results will be incorrect making a weak battery appear good and good battery appear bad.
Black lead of voltmeter to negative(-) of battery and Red lead of voltmeter to positive(+)
make sure everything is turn off....int/boot lights, ignition key out,  door close.
Compare results with table below

Readings:

12.6 V – 12.7 V = 100% of Charge

12.45 V – 12.5 V = 75% of Charge

12.3 V – 12.4 V = 50 % of Charge

12.15 V – 12.2 V = 25 % of Charge

3.Hydrometer Test
Tools needed: Hydrometer
Unscrew cell cap. Depress the pump fully and insert the hose at the end of the tube into the cell hole, release pump and electrolyte should start flowing into the tube which then should floats the weight. Look at the tube at eye level and this should give you a reading.

1.240 – 1.260 = 100% Charged

1.210 – 1.240 = 75% Charged

1.180 – 1.210 = 50 % Charged
1.150 – 1.180 = 25 % Charged

4.High rate discharge (Load) test

Tools needed: Load tester
Connect load tester positive lead to positive terminal negative lead to negative terminal. Find the cold cranking amp (CCA) for your battery and half it (half 550CCA = 275A). Set the load tester to 275A and leave it for 15-20seconds during the test the battery voltage should not drop below 9.6 volts.
OR
Tools needed: Voltmeter
Unplug EFI fuse, connect volt meter to battery and crank the engine voltage display should not drop below 9volts.

5.Amp Draw Test
Tools needed: Ammeter
With the car off (key out, no lights on, doors close, boot close....), disconnect the battery negative (you might want to hook up a jumper wire first so you dont loose your memory then once ammeter is wired up you can unhook the jumper wire) and hook up the ammeter in series the result should  around 30-50 mA

6.Digital Battery Test

This is what battery dealers use now a days.  make sure the voltage of the battery is not below 7 volts because the tester will be powered by the Battery being tested. Connect tester to battery terminals positive to positive and negative to negative. When connected the tester should display the voltage of the battery. Using up down arrow buttons choose the CCA of your battery eg 550 CCA, then press test button. The digital battery tester might show CH which means battery need charging to continue the test or give you a result of PASS (no faults found and battery is in good order) or FAIL ( Something is wrong with the battery).

4841 Alternator

An alternator is basically a generator but instead of running on fuel an alternator in a car converts mechanical energy to electrical energy in the form of alternating current (AC).  


On car test 
Voltage (when car is off)=12.6v
Current (No load)=17A
Voltage test (when car is running)=14.6v
Load test (heater on light on)= 45A




Off car test

Rotor winding to ground test
Set the ohmmeter on 2K.  Place the black lead on the centre of the rotor shaft . Place the red lead on the slip-ring.There should be no circuit between the rotor shaft and the slip ring. 
The meter should read infinity O.L

Rotor winding continuity test

Set the Ohmmeter on 200Ω, test for internal meter resistance by touching the two leads together.Place one end of each lead on the slip rings . Result minus  internal meter resistance.The result should be 2-6Ω

Testing stator winding resistance

et Ohmmeter on 200Ω, Remember that the internal resistance of the meter must be taken away from the actual reading.  Select the common terminal (the one with the most wires attached) of the stator winding terminals A to D.  Connect the black lead to the common point.  Connect the red lead to the other terminal one after the other and record their resistance they should all be approximately the same from 0.0Ω - .2Ω

Testing stator winding earth leakage test
Set the meter on 2K.  Place the common lead on the body of Alternator as indicated.

Place the red lead on the common stator winding terminal (the terminal with more wires connected to it). There should be no circuit between the stator winding and ground.  The meter should read infinity.

Testing rectifier positive diodes

Set the meter on ‘Diode Test’  mode. Put the common lead on B terminal. 

Then touch the positive lead on each of the P terminals and record the readings.The voltage

should be 0.6-0.7 V.

Testing the rectifier negative diodes

Testing voltage regulator

the regulator i tested show a voltage of 12v which is a bad regulator. Good regulator should show 14v

Other ways of testing a alternator

Using a test light tough all the terminals and do ground test. places where should be connected should light places that shouldn't be connected the light shouldn't come on.

4841 AC TO DC

BLOCH

AC

Diode Bridge

LED

Capacitor

5v Regulator

LED
Capacitor

DC 5v out put

CIRCUIT 

LOCHMASTER 

PARTS LIST 

4x Diode 1N4007 1A 1000v

1x 560R resistor

1x 390R resistor

1x Red led 3mm 30mA 2.2v

1x Green led 3mm 30mA 2.2V 

2x Capacitor 35uF 

1x 5v Ragulator 1A 7805 

HOW IT WORKS 

AC goes through bridge rectifire(diode) comes out DC goes through filter (capacitor) then indicator(red led) then go through 5V ragulator  which the turns the 16V DC to 5V DC  then goes through another filter (capacitor) then another indicator ( green led)  then DC out put.

CIRCUIT BOARD TESTING

Red lead of multimeter to yellow wire on the board 

 Red lead of multimeter to red wire on board

4841 Diode and LED

What is a diode

Diodes is a electrical component that is use in circuits to only allow electric currents to go one way. 

P= P-type (hole)             A= Anode +
N= N-type (electrons)    K= Cathode -

How to pick a diode.
-Choose the correct amp needed
-Choose the correct voltage needed


Diodes are sold in amps and voltage
eg      1A                       3A
     1N4001   100v    1N5408
     1N4004   400v    1N........
     1N4007  1000v   1N.......


above are example of diode.1N4001 can handle up to 1A and 100v. 1N5408 can handle 3A and 100v. 1n4007 can handle 1A and 1000v and so on....




LED (Light Emitting Diode)

LED's are diodes that light up.They were first use as indicators but are now use in many devices eg TV, Cars, Cell Phones..... They come in many colours (even once that can change colours) , shapes and different sizes  8 mm, 5 mm and 3 mm.




Work out resistor to use with it
R=resistance
Vs= Voltage supply
Vl = LED Voltage (2V for all but 4V for white and blue LED)
I= LED Current needed (20mA change to A =0.02A for formula)


Fomula
R=(Vs-Vl)/I


eg R=(12V-2V)/0.02
      R=500ohm

4841 Transistor

P= P-type (hole)             A= Anode
N= N-type (electrons)    K= Cathode


DIODE

TRANSISTOR

A transistor is a component used to amplify and/or a switch by using small electric signals.

NPN= Not Pointing In
PNP=Point iN Plz


How it works
To work as a amplifier a high voltage can be pass through the collector (input) and emitter (output) the base is the switch a voltage less than 1v can be use (but not more than 15v or else the transistor will over heat and melt) when base gets a signal, this allows voltage to pass from collector to emitter this acts as a amplifier. 
You can also get transistors that will turn off when base gets a signal these are PNP type transistor.


How to test
Tools need :multimeter on diode test 
There are six positions you should place with your multimeter probe to get a conclusion.
Like a diode, current will only go one way the leg that gives a reading with the two other leg is the base. now that you have found base next is to find emitter, keep one probe on base and with the other test the other two leg and the highest reading out of the 2 leg is the emitter.

4841 Switches and Relay

What is a switch use for
A switch is basically use to make or break a circuit


Switch Electronics abbreviation
SPST = single pole, single throw 

SPDT= single pole,double throw

DPST=double pole,single throw

DPDT=double pole,double throw

Relay
Relay is a switch that operates electrically.

How it works
Picture on the right. The top spring is connected to a leaver that holds it connected to the outer right leg, when voltage is pass through the coil it creates a magnetic field when the correct voltage passes through the coil  (you can buy relay that responds to 6v or 12v) the magnet gets strong enough to attracts the armature and the leaver which connects to the middle leg, depending on how you connect the relay to the circuit this make or breaks the circuit.






http://en.wikipedia.org/wiki/Relay

85  Negative coil 

86  Positive coil

30,87  Terminals Switch normally open (NO)

30, 87A   Terminals Switch normally closed (NC)

85  Negative coil 

86  Positive coil

30,87  Terminals Switch normally open (NO)

Relay with diode

On some relays there is a diode build in to protect circuit components from back EMF (electromotive force)  produced by the relay coil a diode is installed next to the coil.

Car alarm Signal light

Four 4 pin relays switching electric window motor by Roman B

Two 5 pin relays switching electric window