Different types of solid state relays (SSR) and their working

Classification of Solid State Relays (SSR)

SSR Definition: A solid state relay may be defined as an electrical switch that changes its state when an external voltage is applied to it. Solid state relay has a capability to control a larger load current or voltage.

There are mainly three types of Solid State Relays:

  1. Reed-Relay-Coupled SSR
  2. Transformer-Coupled SSR
  3. Photo-coupled SSR

Let us discuss these solid state relays one by one.

1)      Reed-Relay-Coupled SSR’s

Reed Relay Coupled SSR
Reed Relay Coupled SSR

Above circuit shows the circuit diagram for Reed Relay coupled SSR. In this type of SSR control signal is applied directly or using preamplifier (if control signal is weak) to the coil of a reed relay. This relay causes the operation of the trigger circuit which is used to trigger the power transistor or TRIAC.

2)      Transformer Coupled SSR’s

Transformer Coupled SSR
Transformer Coupled SSR

Second type of solid state relay is transformer coupled SSR. It uses a transformer for sending the control signal from primary windings to the secondary winding. Secondary winding is connected to the trigger circuit which is used for the triggering of thyristor switch. It also uses DC-AC converter if the input control signal is DC because transformer can not work with DC.

3)      Photo coupled SSR:

Photo Coupled SSR
Photo Coupled SSR

Another type of solid state relay is photo coupled SSR. Above figure shows the circuit diagram of the photo coupled SSR.In this type of SSR control signal is applied to the infrared source or light source like LED. When it emits light, a photo sensitive element like photosensitive diode, photo-sensitive transistor or a photo-sensitive thyristor will sense that light and operates the load current through trigger circuit. It is obvious that the input and output circuit are completely isolated from each other since only light is used between them. Therefore sometimes this SSR is also called as “optically coupled” or “photo-isolated” SSR.

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How To Build Home Made Electric Fan Regulator – Mini Project

Hi friends, in this article we will see one simple mini project for electronics and electrical engineering students. We all are familiar with electric fan regulator which we use for varying the fan speed. The basic principle behind regulator is a change of resistance.

This article is written by Mohamed Maricar & Modified by Mayuresh Joshi

Cheap and Best Electrical Fan Regulator

Electric Fan Regulator

Fig (A): shows the full view of connection diagram of the product
full-view-of-electric-fan-regulator
Fig (B): shows full view of the product and external side
PCB-Without-Resistance
Fig (C): shows the PCB without resistance

 

Components required:

  1. One Resistance = Rs. 0.15
  2. 28 Resistances = Rs.4.20
  3. One PCB = Rs.5.00
  4. One Rotator Switch = Rs. 8.00
  5. One Plastics Cabinet = Rs.5.00
    Total Cost = Rs. 22.20 Rupees Only

Steps to build electric fan regulator:

  1. First, we have to take PCB as shown in Fig (C)
  2. Then we put the Resistance and solder in PCB holes as shown in fig(A)
  3. Now we connect PCB ends with rotator switch as in fig (A)
  4. We connect rotator switch with AC supply
  5. Now if we vary the rotator switch we can get the different speed of motor
    1. The Resistance network is used to drop the voltages in five steps that are level
    2. The first step 13 volts dropped second steps 26 v third step 39v fourth step 53v
    3. By dropping the five level used to vary the speed of motor
    4. By dropping voltages we can vary the speed of electrical fan motor
  • What is my idea?
    My idea is to design a new circuit to reduce the cost and increase the performance of the product
  • What does it do?
    It regulates the speed of electric fan motor by dropping a.c. voltage in different level
  • How does it work?
    It is working by Ohms law and circuit theory principles
  • What makes my idea Unique?
    Cheap and best

Advantages of my product

  1. Cheap cost
  2. Low care
  3. Low power loss
  4. Low heat loss
  5. Good performance

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Accidental Vehicle Lifting Robot – Electronics Mini Project

Nowadays the number of road accidents increasing frequently. Whenever vehicle accident occurs on the road there may be a high possibility of traffic. In such cases, if we could able to move that accidental vehicle from the road, we can easily avoid the traffic. To make this possible we can build an accidental vehicle lifting robot using the embedded system. You can build its prototype using a small vehicle which you can easily found in the toy store.

Accidental Vehicle Lifting Robot

Accidental Vehicle Lifting Robot
Accidental Vehicle Lifting Robot

 

Working of Accidental Vehicle Lifting Robot

The working of this project is based on the microcontroller which is connected to a motor to move the accidental vehicle. Also, the microcontroller is connected to a chain based rod to lift the vehicle.

The complete circuitry of this project contains microcontroller board which has a robotic platform, keypad, electric motors to move the vehicles and lifting the chain based rod. These motors will be moved accordingly to the instruction given through keys connected to the microcontroller.

Components required

Hardware:

  • AT89c52
  • Robot platform
  • Driver circuit
  • Motor for lifting
  • Controlling keys
  • 12 v battery

Software:

  • Embedded ‘C’
  • RIDE/KEIL to write code
  • ISP to burn the chip

Advantages Accidental Vehicle Lifting Robot:

  • Low cost
  • automated operation
  • Low Power consumption

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Sending SMS from No Signal Area – Electronics Mini Project

Hi friends, in previous article we have seen Zigbee and GPS project which tracks a vehicle. Today we will build another innovative electronic project which will send a SMS from No Signal Area. There are many locations where we get poor range or completely no range. So using this embedded system we can send a SMS from such locations. The only condition we need here is, we should have a mobile network at the receiving end of Zigbee module.

This is low cost project and highly innovative. You can build such projects for your final year engineering submissions also.

Sending SMS from No Signal Area

Objective

The main objective of this micocontroller project is to send a SMS from No Signal area which is also known as Black Spot area using Zigbee and GSM module.

Components:

Hardware

  1. 8051 family development board
  2. power Supply
  3. Zigbee modules
  4. GSM modem.
  5. Max232

Software

  1. Embedded ‘C’
  2. RIDE to write code
  3. ISP to burn the chip

Block Diagrams

Zigbee Transmitter Block Diagram

Sending SMS from No Signal Area Transmitter Block Diagram

Zigbee Receiver Block Diagram

Sending SMS from No Signal Area Receiver Block Diagram

Power Supply:

Power Supply

Description

As already stated, this project is useful for creating signal, using GSM module we can send SMS through that signal to destination. In this project we are using two different frequencies. Zigbee has frequency 2.4GHz and GSM has frequency 1800 MHz.

Main circuitry of this project contains two embedded development boards. One contain Zigbee and Keypad and other contain Zigbee and GSM. We need to place first board in No signal (Black spot) area. Other development board which contains Zigbee receiver and GSM module is kept in area where there is mobile network.

When you type a message using keyboard and hit enter from No signal area, Zigbee transmitter will send a signal with message to the receiver end. Receiver end of Zigbee also has GSM module which will send that SMS to destination mobile.

Watch this Video

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Wi-Fi Based Industrial Automation – Electronics Mini Project

Hi friends, in this project we will see How to automate industrial equipment using Wi-Fi network. We are going to operate electrical equipment from the central control point. This is low cost and flexible mini project which you can use for your final year project. It is also secured industrial automation system.

Components Required

  1. Rabbits Processor – RCM5600W
  2. RS 232 cable
  3. PC
  4. Industrial equipment to be controlled using Wi-Fi network

Block diagram

Receiving:

Block diagram for Industrial automation
Block diagram for Industrial automation

 

Transmission:

transmission
Transmission

Description

In this automation system, devices to be operated are connected to the Rabbit’s processor. You can see devices like Fan, Heater, and the electric bulb is connected through the Realy circuit. Please read Data sheet of Rabbits Processor for details. The current status (on, off) of the device is sent to the web page which is accessed by the end user. For this, you need a PC which is connected to the Rabbits Processors Wi-Fi network.

When the end user sends an action for operating any device, it will be received by Rabbits Processor and get executed. In this way, automation of industrial equipment will take place using Wi-Fi.

Industrial automation
Industrial automation
Source: RCM5600W Datasheet (http://www.digi.com/pdf/ds_rcm5600w.pdf)

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Clap Switch Circuit: Electronics Mini Project

Hello friends, this post provides you a simple mini project of clap switch. This clap switch mini project is useful for operating electric equipment like fan, bulb, radio etc. by using clap sound. For getting the sound of clap we will use a small microphone in this mini project as shown in clap switch circuit diagram below.

Circuit Diagram

Clap switch circuit diagram
Clap switch circuit diagram

Construction of Clap Switch

We have used a microphone which converts sound wave into an electric signal. This electric signal from the microphone is then amplified by using a transistor Q1 as shown in circuit diagram. Transistor Q1 is used in common emitter mode. The output of transistor i.e. signal from the collector of the transistor is then fed to the flip-flop circuit which is also known as bistable multivibrator circuit.

Transistors Q2 and Q3 are used to make a flip-flop circuit. We know that in a flip-flop circuit only one transistor is conducted and other is in cut off. Now when this second transistor gets a trigger pulse from outside it will be in conduction mode and the first transistor will be cut off. Therefore the output of the flip-flop will be always either 1 or 0.

Components required

Resistor Capacitor Semi Conductors Other Components
R1=15KO,  R3=270KO,  R4=3.3KO R5,R6=1.5KO R7,R8=10KO, R9,R10=27KO R13=2.2KO R2,R11,R12=2.2MO, C1=1000µf/16v
C2=.01µf, C3,C4=.047µf
Q1,Q2,Q3= BC548D2,D3,D4= IN 4148D1,D5=IN 4007,

Q4=BC368

 

T1=12v/500mA Transformer,Mic= Condenser Microphone,

K1= 12V Relay,    B1= Bulb or Load

 

Working of Clap Switch

Working principle of clap switch circuit is based on the above discussion. In this clap switch, circuit clap is acting as a pulse for the flip-flop circuit. For example, suppose initially output is high (i.e. on state), when clap sound is generated output becomes 0 and the equipment connected to the output of clap switch circuit will be in off state. Thus by generating clap sound, the output get reversed.

The output of flip-flop circuit is unable to drive the relay circuit. Therefore we have to use an amplifier for amplifying the current. To overcome this problem we have used a current amplifier by using a transistor Q4 in common emitter mode. Thus the output of this current amplifier is sufficient to operate the electromagnetic relay which is used to connect the electrical equipment to the clap switch circuit.

The basic use of a relay is that we can connect or disconnect the electrical equipment from the supply. Therefore we have to use a relay in power line as shown in circuit diagram.

Tip: Following figure shows the pin configuration of mic that we are using in our clap switch circuit.

Microphone pin configuration
Microphone pin configuration

Here terminal ‘b’ is connected to the ground and terminal ‘a’ is connected to the supply through a resistor as shown in circuit diagram.

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DTMF Based Load Control System (Home Automation): Electronics Project

This project works on the principle of DTMF (Dual-tone multi-frequency). This circuit can be used to control or on/off the load i.e. electric equipment like a fan, bulb, water pump, etc.

We know that in industries, loads are distributed over large distances, and it is not convenient to operate all those equipment time to time and it is also time to consume.

Also in agricultural fields, water pumps and other electric systems are spread over the large area and it is hard to operate these systems to farmers. We can use this circuit in the home too, therefore this can also be called as DTMF based home automation project. Keeping all these problems in mind, a DTMF based load control system is designed as follows.

In DTMF based load control system, a cell phone (mobile) is connected to the circuit from its audio output (audio jack) to receive the tone generated by the operator mobile. Whatever audio signal (in the form of frequency) is received from mobile then decoded (to its digital code) by the use of DTMF decoder which is one of the main parts of the project. Then this digital code goes to 8051 microcontrollers which on/offs respected relay to control that electric equipment. a relay driver IC is interfaced with the microcontroller to actuate the relays.

Components required:

Sr. no Equipment Quantity
1 IC 8051 MC 1
2 MT 8870 DTMF IC 1
3 Crystal (3.579545mhz) 1
4 VOLTAGE REGULATOR 1
5 2 LINE LCD DISPLAY 1
6 CRYSTAL OSCILLATOR(11.0592mhz) 1
7 DIODE 1
8 PUSH BUTTON 1
9 LEDS 4
10 RESISTER(220O,4.7kO,10kO) BOX
11 CAPACITORS(10uf,1000uf) 5
12 RELAYS 2
13 Bc547 2

DTMF based load control system block diagram
DTMF based load control system block diagram

DTMF based load control system circuit diagram
DTMF based load control system circuit diagram

Software requirements: Keil compiler

Languages: Embedded C or Assembly

DTMF IC (MT 8870) Pin configuration

MT 8870 pin diagram
MT 8870 pin diagram

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Street Light Circuit Using LDR Electronics Project

In this mini project of the street light circuit using LDR, we are going to operate street light using a light dependent resistor (LDR).

Objective

The purpose of this mini project is to switch off the street light in the day and switch on the street light in the night.

Components required

Following are the components which we are going to use for this mini-project of the street light circuit using LDR:

  1. LDR (R1)
  2. Resistors : R2 = 100K, R3 = 1K, R4 = 1K
  3. Transistors: Q1 = BC 107, Q2 = SL100
  4. K1 = SPDT relay
  5. 230V Lamp
  6. 9V battery
  7. Fuse (optional)

Description

The following figure shows the circuit diagram of the street light controller using LDR. Here we have used a 230V lamp which will turn on in the night and get turned off during the daytime.

Street Light Controller Circuit Diagram
Street Light Controller Circuit Diagram

Light dependent resistor i.e. LDR is the main component used in this mini-project. We know that the resistance of the LDR decreases as the intensity of the light increases and vice versa. The Same principle is used here. When there is the presence of light the resistance of LDR will be low. So the voltage drop across the pot R2 will be high, which keeps the transistor Q1 on. The collector of Q1 (BC107) is coupled to the base of Q2(SL100). So Q2 will be OFF and so do the relay. The bulb will remain OFF.

Similarly at night the intensity of light decreases and resistance of LDR increases. Therefore the resistance of pot R2 decreases below 0.6V. This makes transistor Q1 OFF which in turn makes Q2 ON. The relay will be energized and the bulb will glow.

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