HOW TO CONNECT ELECTRONIC COMPONENTS

Here is a quick post on how to connect the basic electronic components correctly. These are cuts from my earlier post. This post is due to a suggestion  from my friend. He thought that a post like this can be used for quick reference and will be helpful to the starters. If you want to knew more about each components check out my other posts.

CONNECTING LED

A LED is a two-terminal electrical component, to identify them

Positive terminal can be identified as the longer leg and shorter leg is the negative terminal.
                         OR
If you look inside the LED you can see two small lead, fat one looks like a flag which is the cathode (negative) and other one looks almost straight which is the anode (positive). The symbol of LED is:-

CONNECTING RESISTOR

A resistor is a two-terminal electrical component

Resistor can be connected either way, that means it have no positive and negative terminal. Both symbols below are used to represent resistor in a circuit diagram. You can use any one of the two symbols:-

CONNECTING CAPACITOR

A capacitor is a two-terminal electrical component.

The ceramic capacitors can be connected either way, that means it have no positive and negative terminal. The symbol used for the ceramic capacitors in a circuit diagram is:-

The electrolytic capacitors have a positive terminal (longer leg) and negative terminal (shorter leg). The symbol used for the electrolytic capacitors in a circuit diagram is:-

CONNECTING LDR

LDR is also a two-terminal electrical which can be connected either way, that means it have no positive and negative terminal. The symbol of LDR is :-

CONNECTING NPN BJT
                                                  
I have marked the  collector (C), base (B) and emitter (E) pins on a real NPN BJT and also on the symbol

CONNECTING PNP BJT

I have marked the  emitter (E), base (B) and collector (C) pins on a real PNP BJT and also on the symbol

CONNECTING 555 TIMER IC

For connecting 555 timer check out this post The 555 timer IC pinout. I have marked each pin on a 555 timer IC and here is the symbol of 555 timer IC:-

Electronic Symbols | Schematic symbols

This post is for the starters out there who is having trouble in understanding the symbol of the circuit. I should have added this post before getting in to projects, here it is because of the request from my friend. I will add new symbol as we use them in our circuits. If you want more symbol OR have doubts on symbols, just leave a comment and I will help you.

RESISTOR

CAPACITOR
        1.electrolytic capacitor

        2. Ceramic capacitor

LED

BATTERY

LDR

555 TIMER IC

PNP TRANSISTOR

NPN TRANSISTOR

SPEAKER

SWITCH
     

PUSH SWITCH

GROUND CONNECTION

DIODE

BISTABLE MODE OF 555 IC

Bistable mode or Schmitt trigger :

A Bistable Mode or what is sometimes called a Schmitt Trigger, has two stable states, high and low. So in bistable mode 555 can operate as a flip-flop. Taking the Trigger input low makes the output of the circuit go into the high state. Taking the Reset input low makes the output of the circuit go into the low state. Remember that the discharge pin (pin 7) is not connected and no capacitor is used. Uses include bounce-free latched switches.

WORKING OF BISTABLE 555

In bistable mode, the 555 timer acts as a basic flip-flop. The  trigger and reset inputs (pins 2 and 4 respectively on a 555) are held high via Pull-up resistors while the threshold input (pin 6) is simply grounded. Thus configured, pulling the trigger momentarily to ground acts as a ‘set’ and transitions the output pin (pin 3) to Vcc (high state). Pulling the reset input to ground acts as a ‘reset’ and transitions the output pin to ground (low state). No capacitors are required in a bistable configuration. Pin 5 (control) is connected to ground via a small-value capacitor (10nF) pin 7 (discharge) is left floating.

MONOSTABLE MODE OF 555 IC

MONOSTABLE MODE :-

As I promised here is the post on monostable mode of 555 timer IC. In this mode, the 555 timer functions as a “one-shot” pulse generator. The name “monostable” meaning “one stable state”.

APPLICATION :-

Applications include timers, missing pulse detection, bouncefree switches, touch
switches, frequency divider, capacitance measurement, pulse-width modulation
(PWM) and so on. For example monostable 555 circuit is ideal for projects at exhibitions, which needed to work when a visitor pushes the button to start the project’s mechanism moving, and the mechanism will automatically switch off after the time you set.

WORKING OF MONOSTABLE 555 TIMER

In this mode 555 acts as a pulse generator and the pulse starts  when the 555 timer receives a input at the trigger input (pin 2) that falls below a third of the voltage supply.The width of the output pulse is determined by the time constant of an RC network, which consists of a capacitor (C) and a resistor (R). The output pulse ends when the voltage on the capacitor (C)  equals 2/3 of the supply voltage( Vcc). The output pulse width can be lengthened or shortened to your need just by adjusting the values of the capacitor (C) and a resistor (R).

CONNECTION :-

Reset (pin 4) and pin 8 is connected to positive voltage (Vcc).

Discharge pin (pin 7) and threshold (pin 6) pins share a common node (means connected).

Resistor R is connected between the Vcc and the common node that is shared by the discharge pin (pin 7) and threshold (pin 6).

Capacitor C is connected between the common node that is shared by the discharge pin (pin 7) and threshold (pin 6) and GND.

Pin 1 is connected to GND.

A 10n capacitor is connected between control (pin 5) and GND.

Here is all about monostable mode of 555 timer IC. My next post will be on bistable mode of 555 timer IC. If you have any doubts or you like the post, put it in the comment box below.

ASTABLE MODE OF 555 IC

ASTABLE MODE

Here is the post about the different working mode of 555 timer IC as I promised on the 555 timer post. An Astable mode 555 timer IC has no stable state – hence the name “astable”. That means output continually switches state between high and low without any intervention from the user, called a ‘square’ wave. This type of circuit could be used for switching a motor on and off at regular intervals. It can also be used to flash lamps and LEDs, and is useful as a ‘clock’ pulse for other digital ICs and circuits.

CONNECTION :-

Reset (pin 4) and pin 8 is connected to positive voltage (Vcc).

Resistor R 1 is connected between Vcc and the discharge pin (pin 7).

Trigger (pin 2) and threshold (pin 6) pins share a common node (means connected).

Another resistor (R 2) is connected between the discharge pin (pin 7), and the common node that is shared by the trigger (pin 2) and threshold (pin 6).

Capacitor (C 1) is connected between the common node that is shared by the trigger (pin 2) and threshold (pin 6) and GND.

Pin 1 is connected to GND.

A 10n capacitor is connected between control (pin 5) and GND.

OUTPUT

In astable mode, the 555 timer puts out a continuous stream of rectangular pulses having a specified frequency at output (pin 3).

My next post will be on monostable mode of 555 timer IC. If you find this post useful, let me know it through the comments.

LED DIMMER

This is a simple circuit that will adjust the brightness of one or more LEDs from 5% to 95%. I have used only only one LED. Only place where you can go wrong in this project is while connecting the diode, so connect the diode properly.

I will add the connections later.

In my breadboard arrangement I have not connected the 100n between the pin5 and negative rail and the resistor I used is 220R instead of 330R in the circuit diagram.

COMPONENTS REQUIRED:

1. 555 timer IC
2. 47k POT
3. 1N4148 diode x2
4. 1k resistor
5. 330R resistor
6. 100nf capacitor (code 104) x2
7. LED
8. Battery

FADING LED

If you want a fading effect on the FLASHING LED project check this out. This circuit will make the LED fade up and down in the same manner.By adjusting the value of resistor you will get a better fading effect. The resistor connected to the LED is important in this circuit.

IF CIRCUIT IS NOT WORKING

1. Firstly check the transistor connection
2. Usually the mistake is made while connecting the 220mf capacitor, circuit is little confusing there, so look at my breadboard connection and the circuit diagram properly.

I will add the connections later.

COMPONENTS REQUIRED :

1. 555 timer IC
2. 220mf capacitor
3. 33k resistor
4. 470R resistor
5. BC547 transistor
6. LED
7. Battery

FLASHING LED

This is a simple LED project for starters and one of the first LED project that I did .It will make the LED flashing at the rate I decide . I had lot of fun doing this one , every time I changed the value of resistor or capacitor , LED keep changing the time between flashing . Let’s build this thing.

Connection :-

1 . Connect pin 2 and pin 6 of 555 IC
2 . Connect pin 4 and Pin 8 of 555 IC
3 . Connect 47mF capacitor +ve ( longer leg ) to pin 2 and -ve to ground.
4 . Connect +ve (longer leg leg ) of LED to pin 3 and -ve to pin 1
5 . Now connect one of the 10k resistor between pin 8 and pin 7
6 . Now connect other 10k resistor between pin 7and pin 6
7. Finish the circuit with battery connection , +ve to pin 8 and -ve to pin 1

If you have problem in identifying the pins of 555 timer IC checkout my post on the 555 timer IC which helps to identify the pins and the function of each pins.

If your connection are correct LED Will be flashing . If you are haveing problem with circuit , leave a comment and I Will help you.

Components Required :-

1. Resistor – 10k x 2
2. Capacitor – 47mF
3. White LED
4. 555 IC
6. Wire
7. 9V battery

SIMPLE TRANSISTOR CIRCUIT

This is the simplest circuit you can make with a transistors. You can use any NPN transistors. Here I have used BC 547. In this  project the transistor is turned on via a finger.

Connect the LED, 220 ohm resistor and transistor as shown in the circuit. Touch the top point with two fingers of one hand and the lower point with fingers of the other hand and squeeze. As you press harder, the resistance of your finger decreases. This allows more current to flow into the base and the transistor turns on more and more. Your body has resistance and when a voltage is present, current will flow though your body (fingers). The transistor is amplifying the current through your fingers and this is enough to illuminate the LED.

If you have trouble in identifying the base, emitter, and collector check out my post on the BJT.

CONNECTION

1. Connect emitter (E) of the transistor to negative terminal of battery.
2. Resistor:- Connect the resistor between the collector (C) and negative of the LED
3. Now connect the positive terminal of both LED and battery.
4. Now connect the touch wire and if you touch those wire LED glow.

COMPONENTS REQUIRED :

1. BC 547 Transistor
2. 220R Resistor
3. LED
4. Battery

To make sure this is working simply press on the two wires and the LED will illuminate brighter and if not leave a comment and I will help you.

SIMPLE SECURITY

This is the simple security system that you can build for your own.You have already seen in movies , somebody cross the red laser line the alarm starts. You can build something like that for your own room.

Here I have placed a buzzer but you can also place a LED or other small project.

SETUP FOR THIS PROJECT :-

For setup your security all you have to do is, put a laser (I recommend laser) or a light source such as LED on one end of the door and place the LDR on other end in such a way that laser beam falls on LDR. This project work on the simple principle that, as someone enter your room the laser beam is cutoff. LDR detect this (absence of light) and trigger the buzzer.

CONNECTIONS :-

1. Place the LDR between base and emitter of transistor.
2. Connect a 10k resistor between base and +ve terminal of buzzer.
3. Connect -ve of buzzer to collector of transistor.
4. Now connect +ve of battery to +ve of buzzer and -ve of battery to emitter of transistor.

COMPONENTS  REQUIRED :-

1.BC547 transistor
2.10k resistor
3. LDR
4. Buzzer
5. Battery