Basic Electronics/Electrical Projects & Kits

Get our latest collection of basic electronics projects here -- all tested and reviewed for use in mini projects and main projects or even just as hobbyist projects!
Design Your Own LI-FI Dongle And Speaker Save Rs. 60.00

Design Your Own LI-FI Dongle And Speaker

by KNS Pvt Ltd
Save Rs. 60.00
Rs. 400.00
Rs. 340.00

Summary

Light Fidelity (Li-Fi) is a new paradigm in wireless communication. In this project, you can learn to design a Li-Fi dongle (transmitter) and speaker (receiver) for audio and music applications. The proposed system is a replacement for wired speakers that play audio signals received through the light.

Product Description

How It works?

1. The LED light in a room is used not just to light up the room but also to play music, thus giving benefits of both the worlds. Also, LED bulbs use 85 per cent less energy than
incandescent bulbs and last up to 20 times longer, whereas the majority of Bluetooth modules are battery powered and generally last a year or two only before they need replacement. Hence the proposed system is energyefficient over Bluetooth version.

2. You can receive Li-Fi data as long as you are in the range of the light being emitted by the LED light source. Hence, the range depends on the strength of the light being emitted.

3. Connectivity needs to be established between the Bluetooth transmitter and the receiver, whereas with Li-Fi any user can receive data and play music on his speaker by simply keeping the receiver in the range of LED light source.

4. The proposed system can be used with any audio system by just connecting the Li-Fi dongle to its audio output jack, with no pairing and connectivity requests. This overcomes the problem of connecting a Bluetooth speaker to audio systems that do not have USB port and Bluetooth support, which is otherwise a tougher task.

5. The proposed Li-Fi dongle and speaker costs lower than a Bluetooth dongle and speaker. It uses a Li-Fi dongle to transmit audio signals from a source such as mobile phone, and a Li-Fi speaker with solar cells at the receiver end to receive audio signals without wires. The proposed Li-Fi dongle is connected to the audio jack output available on mobile phones. It has an LED through which audio/music signals are transmitted as light signals. These light signals are captured by the Li-Fi speaker through the solar cell array.

Sunset Lamp
Rs. 100.00

Sunset Lamp

Sunset Lamp

by KNS Pvt Ltd
Rs. 100.00

Summary

This kit is based on the principle of Light dependent resistor . Thus when the sun sets the ambient light in the environment decreases and thus the light glows up.

Learning

Things which you will learn:

*Application of NE555 in bi stable mode.
*Concepts related to the working of Light Dependent Resistors.
*Application of TRIAC BT136.
*Application of Zener Diode.

Product Description

Build this automatic sunset light , which will light up when its dusk and will help in conserving electricity .

Working

The circuit uses popular timer IC NE555 as a Schmitt trigger to give the bistable action. The set and reset functions of the comparators within the NE555 are used to give the instantaneous action. The upper threshold comparator of IC1 trips at 2/3Vcc, while the lower trigger comparator trips at 1/3Vcc.The inputs of both the threshold and the trigger of NE555 are tied together and connected to the voltage divider formed by LDR1 and
VR1. The voltage across LDR1 depends on the light intensity.

In daylight, LDR1 has low resistance and the input voltage to the threshold comparator goes above 2/3Vcc and its output becomes zero, and the lamp remains off.
At sunset, the resistance of LDR1 increases, and the voltage at the input of the threshold comparator decreases below 2/3Vcc and that of the trigger comparator goes below 1/3Vcc. As a result, the outputs of threshold and trigger comparators go high. Thus it completes the power supply to the lamp through triac1. LED1 glows to indicate the high output state.

 

Click here to Download PDF

 

Cellphone Detector Mobile Bug Save Rs. 50.00
Rs. 300.00
Rs. 250.00

Cellphone Detector Mobile Bug

Cellphone Detector Mobile Bug

by KNS Pvt Ltd
Save Rs. 50.00
Rs. 300.00
Rs. 250.00

Summary

This handy, pocket-size mobile transmission detector can sense the presence of an activated mobile phone from distance of one and- a half meters. So it can be used to prevent the use of mobile phones in examination halls, confidential rooms, etc. It is also useful for detecting the use of mobile phone for spying and unauthorized video transmission.

Learning

Things which you can learn:

*Working of CA3130 as current to voltage converter.
*Application of transistor as an amplifier.
*Application of NE555 as an amplifier.

Product Description

Build yourself a mobile detecting bug and become an expert in finding out hidden mobile phones in sensitive areas like LPG godown etc.

Working:

The circuit can detect both the incoming and outgoing calls, SMS and video transmission even if the mobile phone is kept in the silent mode.The circuit uses a 0.22μF disk capacitor (C3) to capture the RF signals from the mobile phone.The disk capacitor along with the leads acts as a small gigahertz loop antenna to collect the RF signals from the mobile phone.

Op-amp IC CA3130 (IC1) is used in the circuit as a current-to-voltage converter with capacitor C3 connected between its inverting and non-inverting inputs.

When the mobile phone signal is detected by C3, the output of IC1 becomes high and low alternately according to the frequency of the signal as indicated by LED1. This triggers monostable 555timer.

 

Click here to Download PDF

“What’s Included In This Box”.

 

S.No Component Quantity
1   Capacitor 22pF ceramic 2
2   Capacitor 0.22uF ceramic 1
3   Capacitor 100uF 25V electrolytic 1
4   Capacitor 47pF ceramic 1
5   Capacitor 0.1uF ceramic 2
6   Capacitor 0.01uF ceramic 1
7   Capacitor 4.7uF 25V electrolytic 1
8   IC CA3130 1
9   IC NE 555 1
10   LED RED 1
11   Piezzo Buzzer 1
12   Resistor 2.2M 2
13   Resistor 100K 1
14   Resistor 1K 1
15   Resistor 12K 1
16   Resistor 15K 1
17   Tr BC548 1
18   switch on/off 1
19   8-pin base 2
20   Antenna 1
21   PCB - AB4380 - Cell Phone Detector 1

 

Water level Indicator

Water level Indicator

by KNS Pvt Ltd
Rs. 100.00

Summary

The purpose of the water level indicator is to caution a person that a water tank has been filled up to a particular level. This circuit exploits the simple fact that water is a good conductor of electricity. The system is capable of indicating the water level in two ways- visual (by the means of an LED) and audible (by the means of a sound generated by a piezoelectric buzzer).

The placement of two probes (with connections from the circuit) inside the water tank determines the minimum detectable level (MDL). When the water reaches this height in the tank (or any other fluid container), the buzzer is activated and the LED is turned on. Number of ICs used: None.

Product Description

The water level indicator employs a simple mechanism to detect and indicate the water level in a tank or any other container. The level sensing is done by a pair of probes, the resistance between which depends upon the water level in the tank. These probes can be placed in two ways on the walls of the tank or container.

Working

1. Both the probes can be placed at different points on the wall lying at the same level/height from the bottom. This height determines the minimum detectable water level, or

2. The probes can be placed at different points lying at two different heights from the tank bottom. In this case, the probe which is placed higher than the other determines the minimum detectable water level.

When the water-level is below the minimum detectable level (MDL), there is infinite impedance between the two probes. Hence, transistor T2 remains in the cut-off mode and does not conduct. However, when water-level reaches MDL or is above it, the connection between the probes gets completed (through the conducting medium o water) and the base voltage of T2 increases.

This causes the base-emitter junction of T2 to get forward biased and the piezoelectric buzzer is turned on to generate an alarm sound. The path from the emitter of T2 through resistance R3 is responsible for forward biasing the base of transistor T1. This switches T1 from cut-off to conduction mode, thereby driving the red LED to glow. Hence at each instance when water reaches the MDL, both the buzzer and LED indicate this simultaneously.

 

Click here to Download PDF

 

Noise Level Alarm Save Rs. 50.00
Rs. 300.00
Rs. 250.00

Noise Level Alarm

Noise Level Alarm

by KNS Pvt Ltd
Save Rs. 50.00
Rs. 300.00
Rs. 250.00

Summary

Noise pollution can cause hearing loss, hypertension, heart disease, annoyance, sleep disturbance and decreased performance in schools. Build this kit and set the threshold level for the noise and get informed whenever the sound gets exceeded the desired limit and thus prevent damage to the health.

Learning

Noise level monitoring gives a brief hands on concept of cascaded and three stage amplifiers in analog electronics and amplifying a very small signal with high gain transistors

Things which you can learn:
1. Cascaded three stage amplifier
2. Analog electronics
3. Gain in transistors
4. Condensor mic

Product Description

Noise is a serious environmental problem that affects us in our daily life. There is scientific evidence supporting that noise exposure can cause hearing loss, hypertension, heart disease, annoyance, sleep disturbance and decreased performance in schools. Sound-level indicators like the one presented here can help address this problem. This sound-level indicator monitors the sound level and indicates through an LED when the level is above the preset value.

Working

The sound is captured by microphone MIC1 and amplified by first stage high-gain transistor T1. Trimmer potentiometer VR1 is used to adjust the threshold level. the signal is amplified again with second-stage transistor T2. This amplified signal is rectified by diode D1 and the charge is stored in capacitor C10. Diode D1 should preferably be a small-signal Schottky diode such as BAT81, BAT82, BAT83, BAT85 or better. You can use 1N4148 and 1N914 also but the signal from the input should be stronger.

Click To View Circuit Diagram

Click here to Download PDF

Long Range Burglar Alarm Using Laser Torch Save Rs. 75.00

Long Range Burglar Alarm Using Laser Torch

by KNS Pvt Ltd
Save Rs. 75.00
Rs. 450.00
Rs. 375.00

Summary

Most laser torch based burglar alarms work in darkness only. But this Long Range Burglar Alarm can work reliably in the daytime as well to alert you about intruders and burglars. The Burglar Alarm comprises of the laser transmitter and receiver units, to be mounted on the opposite pillars of the possible entry points. Whenever anyone enters to interrupt the transmitted laser beam falling on the receiver, the buzzer in the receiver circuit sounds an alarm. No. of ICs used: 1 Note-Laser torch will not be provided by KnS.

Learning

Things which you can learn:

*Application of NPN transistors for switching purposes.
*Use of the Photo-Darlington 2N5777 for sensing purposes.
*Application of the NE555 timer IC as a multivibrator to generate oscillations of a particular frequency.

Product Description

The range of the Burglar Alarm is approximately 30 meters, which means that the transmitter and receiver units can be placed up to 30 meters apart. Since the laser torch can transmit light up to a distance of 500 meters, this range can be increased by proper orientation of the photo-transistor. However, to avoid false triggering by sunlight, the photo-transistor should be mounted in such a way that it doesn’t directly face sunlight.Build this circuit and prevent theft in your premises.

Working

The transmitter circuit is powered by 3V DC. The multi-vibrator built around NE555 timer (IC1) produces a frequency of 5.25KHz. The body of the laser torch is connected to the emitter of the NPN transistor SK100 (T1) and the spring-loaded lead protruding from inside the torch is connected to the ground.
The receiver circuit is powered by 12V DC. It uses the photo-Darlington 2N5777 (T2) to sense the laser beam transmitted from the laser torch. The output beam signals from the photo-Darlington are given to the two-stage amplifier followed by a switching circuit. As long as the laser beam falls on photo-Darlington T2, the 12V relay (RL1) remains unenergized and the buzzer does not sound. Also, the indicating LED (LED1) doesn’t glow.
When anyone interrupts the laser beam falling on photo-Darlington T2, NPN transistor BC547 (T6) stops conducting while NPN transistor SL100 (T7) is driven into conduction. As a result, LED1 glows and relay RL1 is energize to sound the buzzer for a few seconds (the alarm duration being determined by the values of resistors R15 and capacitor C10 in the circuit). At the same time, the large indication load (230V AC alarm or hooter for louder sounds or any other device for momentary indication) also gets activated as it is connected to 230V AC mains via normally opened (N/O) contact of relay RL1.

Click To View Circuit Diagram

Click here to Download PDF

Zener Diode Tester

Zener Diode Tester

by KNS Pvt Ltd
Rs. 200.00

Summary

Zener Diodes are a very important concept when it comes to the voltage regulator. To effectively control voltage it is essential that the diodes work perfectly. So we bring you a Zener Diode Tester kit which can be used to check zener diodes of 3.3V to 18V. The breakdown voltage of the unknown zener diode is indicated on the pre-calibrated dial of the potentiometer VR1. The tester can also identify the polarity of zener diodes. No. of ICs used: None

Learning

Things which you can learn:

*Concepts related to zener diodes and their application.
*Application of transistor for switching purposes.

Product Description

The power supply section of the Zener Diode Tester provides approx. 20V DC stabilized voltage to the sensor section. The sensor circuit comprises two resistors (R2 and R30, a potentiometer (VR1), a red LED and an NPN transistor BC547 (T2).

Working:

When the linear potentiometer VR1 is adjusted such that the voltage at its wiper arm (red crocodile clip) exceeds the breakdown voltage of the zener diode, the zener diode
conducts and applies the bias voltage at the base of transistor T2, which causes the red LED to light up. When the voltage at the wiper arm (red clip) is less than the breakdown voltage, the zener diode does not conduct and red LED does not glow. For calibration of the zener diode tester, initially, the pointer knob of VR1 is set towards the zero-resistance position. Short red clip of the potentiometer and black clip of the transistor and switch on the tester. The pointer knob of potentiometer VR1 is slowly rotated in a clockwise direction until LED just starts to glow.

This setting of the knob is marked on the paper dial as 0V. Now a zener diode of a known value (for example, 3.3V) is connected between both the clips (red clip to the cathode and black clip to the anode of the zener diode). The knob of potentiometer VR1 is further rotated in the clockwise direction until the red LED just starts to glow. This setting of the knob is marked on the paper dial as 3.3V. Likewise, the dial of potentiometer VR1 is calibrated for other values of zener diodes by connecting known zener diodes to the tester.

For testing an unknown zener diode, it is connected across the clips in correct polarity
and the knob of potentiometer VR1 is rotated until red LED1 just starts to glow. The
voltage shown by the pointer knob on the dial at this setting is the breakdown voltage
value of the zener diode under test. If the zener diode is connected in reverse polarity (red clip to the anode and black clip to the cathode), the LED glows brightly at all settings of the knob above the zero reading, indicating that the zener diode is wrongly connected. The anode and cathode terminals of rectifier diodes can also be identified in this way.


EFY Note: It is not recommended to touch the clips while testing.

 

Click here to Download PDF

 

PC based timer Save Rs. 50.00
Rs. 300.00
Rs. 250.00

PC based timer

PC based timer

by KNS Pvt Ltd
Save Rs. 50.00
Rs. 300.00
Rs. 250.00

Summary

Timers are very useful both for industrial applications and household appliances. The PC Based Timer circuit interfaces with a computer through a D25 pin male connector to switch ON/OFF a device for a particular time interval. The program of the PC Based Timer is written in C language & compiled using the Turbo C compiler. The maximum timing for which the circuit can operate a device is 18 hours. No. of ICs used: 1

Learning

Things which you will learn :

*Application of the optocoupler IC MCT2E.
*Application of the NPN transistor for switching.
*Application of diodes for freewheeling/flyback.

Product Description

The PC Based Timer uses a simple program and interface circuit to switch on/off the appliance via the relay circuit. The circuit is interfaced with the PC with a D25 pin male connector.

Working


The circuit uses the IC MCT2E(optocoupler) which isolates the PC and the relay driver circuits. The MCT2E prevents the PC from any short circuit that may occur in the relay driver circuit or appliance. The glowing of a red LED in the circuit indicates that the appliance is turned on while the NPN transistor BC548 is used as the relay driver.

The program code is written in ‘C’ language and compiled using ‘Turbo C’ compiler. When the program is run, it prompts the user to input the time duration in seconds or minutes to control the appliance.

Click To View Circuit Diagram

Click here to Download PDF

Battery Low Indicator Save Rs. 75.00
Rs. 250.00
Rs. 175.00

Battery Low Indicator

Battery Low Indicator

by KNS Pvt Ltd
Save Rs. 75.00
Rs. 250.00
Rs. 175.00

The purpose of the battery low indicator is to give a visual indication when a battery has been discharged below a certain level. This is especially crucial for re-chargeable batteries that should not be discharged below a certain voltage level. This lower voltage limit depends upon the type of the battery. The battery low indicator circuit can be typically used for 12V batteries to give an indication of the battery voltage falling below the preset value. The indication is in the form of a flickering LED.

Learning from the project

  • Application of the LM319 dual comparator for level comparison.
  • Application of the NE555 timer in astable mode of operation.

Product description

The heart of the battery low indicator circuit is the dual comparator IC LM319 (denoted as IC1) which compares the battery’s voltage to a reference voltage level. Only one of the two independent comparators that are a part of the LM319 is used in the circuit. The two inputs to this comparator are:

  1. The reference voltage, which is applied to the non-inverting input pin (4). It is held constant at approximately 1.2V by the zener diode (D1).
  2. Battery’s voltage, which is applied via a potential divider arrangement built around resistors R2, R3, and preset VR1 and fed to the inverting input pin (5).

The corresponding output is generated at pin 12 of IC1. Preset VR1 is very important as it sets the voltage level at which a visual indication of the low battery level is generated. For example: If the battery under test is of 12 V and an indication is required as soon as the battery voltage falls below 10.5 V, the voltage at the inverting input (pin 5 of IC1) should be adjusted to 1.2 V using preset VR1.

Initially, when the battery is fully charged, the voltage at the inverting input (pin 5) of IC1 is higher than the non-inverting input (pin 4- voltage level held constant at approximately 1.2 V by D1). This causes the output at pin 12 of IC1 to remain low. The reset pin (pin 4) of an NE555 timer (IC2) is connected to the output pin of IC1 and hence, a low gets applied to it correspondingly. Since the reset pin is “active low”, the NE555 is reset continuously and oscillations are not generated at its output (pin 3). As a result, LED1 does not blink.

Considering the example values, when the battery voltage falls below 10.5 V, the voltage at the inverting input (pin 4) of IC1 becomes lower than the non-inverting input (pin 5) and the output at pin 12 of IC1 goes high. This applies a “high” to the connected reset pin of IC2 (NE555 timer) and the astable multi-vibrator built around IC2 starts generating oscillations. LED1 is connected to the output pin (pin 3) of IC2 and hence blinks to indicate low battery voltage and the battery needs to be charged before further use.

 

Click here to Download PDF

 

Power Failure And Resumption Alarm Save Rs. 100.00

Power Failure And Resumption Alarm

by KNS Pvt Ltd
Save Rs. 100.00
Rs. 300.00
Rs. 200.00

Summary

The Power Failure and Resumption Alarm circuit sounds an alarm whenever AC supply mains fails or resumes. The circuit gives an audio-visual indication of the failure and resumption of mains power through a bi-colour LED and a piezoelectric buzzer. No. of IC used: 3

Learning

Thiings Which you can learn:
*Application of the LM556 dual timer IC in the astable and monostable mode.
*Application of PNP and NPN transistors.
*Concept and working of bi-colour LEDs.

Product Description

A simple circuit which provides Audio Visual Indication when the AC supply resumes/fails.
This is important as when the users gets informed about the power failure, he/she can judiciously use the supply from the inverter so that they are not affected due to excessive drain of battery.The heart of the Power Failure and Resumption Alarm circuit is the dual timer IC LM556. When mains is present, the bicolour LED (LED1) glows in green colour while when the mains fails it turns red.

Working:

When mains is present, the PNP transistor BC558 (T1) is in the cut-off state and therefore the bicolour LED glows in green colour. When power fails, PNP transistor T1 starts conducting and bicolour LED glows in red colour. Due to non-availability of Vcc voltage at pin 14 of LM556 (IC2), its output pin (Pin9) remains low and NPN transistor BC548 (T3) does not conduct.

However, a 4700µF capacitor (C7) holds an adequate charge and hence PNP transistor BC557 (T4) conducts and the piezoelectric buzzer (PZ1) sounds continuously for approx. eleven seconds until capacitor C7 discharges completely. When power resumes, bicolour LED glows in green colour and the buzzer beeps for approx. 14 secs.

IC LM556 outputs frequencies in the form of pulses at its pin 9. These pulses are coupled to the NPN transistor BC548 (T3), which conducts and cuts off depending on the output at pin 9 of IC2. A Red LED (LED2) is connected to pin 9 via a 270-ohm current-limiting resistor (R7) to indicate power resumption.

 

Click here to Download PDF

 

Intruder Alarm Save Rs. 75.00
Rs. 250.00
Rs. 175.00

Intruder Alarm

Intruder Alarm

by KNS Pvt Ltd
Save Rs. 75.00
Rs. 250.00
Rs. 175.00

Summary

The Intruder Alarm automatically activates a loud alarm whenever any unauthorized entry is attempted. Unlike other alarms, the Intruder Alarm circuitry does not need replacement of a broken loop. The alarm can be turned OFF just by the simple flick of a switch. The unit power on indication by LED is also provided here for better monitoring.
Build yourself a simple intruder alarm circuit to keep the thieves at bay!! No. of ICs used: 2

Learning

Things which you will Learn :
*Learn how to use LDR sensor.
*Application of basic gates and flip-flop and hex inverters.

Product Description

The Intruder Alarm circuit should be typically fitted to the door of your house, to sound an alarm when anyone pushes the door. This way it alarms you against thieves or intruders. The circuit primarily comprises a transmitter and receiver pair. The transmitter is fitted onto the inside of the door frame while the receiver is fitted to the door panel.

Working:

The transmitter section consists of a laser diode which is powered by a 9V battery. When the switch (S1) in the transmitter section is closed, the laser diode glows. Closing switch (S2) provides power supply to the receiver section. Light falling from the laser diode on the light-dependent resistor (LDR) in the receiver section provides base current to transistor T1 and it starts conducting. This grounds the base of the transistor (T2), so it doesn’t conduct and the alarm remains off. When somebody pushes the door, light incident on the LDR is interrupted and the transistor (T1) stops conducting since the LDR offers a high resistance in the absence of light. Transistor T2 receives base current and starts conducting. The pulse from the emitter of transistor T2 is connected to the inputs of AND gate N1 (IC1). The high output of AND gate is connected to a JK flip-flop (IC2) that works as a latch. As a result, output pin 12 (Q1) of IC2 goes high to cause conduction of transistor T3 and consequent sounding of the alarm. The alarm can be turned off by switch S2.

Note: While testing at EFY Lab, a laser torch was used in place of the transmitter.

Click To View Circuit Diagram

 

Click here to Download PDF

CHIP TALK HOBBY PROJECTS KITS - FOR BEGINEERS Save Rs. 501.00

CHIP TALK HOBBY PROJECTS KITS - FOR BEGINEERS

by KNS Pvt Ltd
Save Rs. 501.00
Rs. 3,500.00
Rs. 2,999.00

Electronics Field is very vast and for those who want to enter this segment in a systematic step by step method, the CHIP TALK offers the best platform where it provides basics of all the necessary concepts required to build projects and moreover it comes with a 40 tested projects circuits to boost your confidence in building and enjoying the projects. 
CHIP-TALK Hobby Projects package includes components and breadboard for prototyping 40 fully tested projects. The book contains the fundamentals of electronics and 40 tested circuits and their descriptions.

Product Description

An Awesome platform for those who are looking to build and learn electronics project with easy access to all the circuits and necessary informations supporting the project.

CHIP-TALK Hobby Projects package includes components and breadboard for prototyping 40 fully tested projects. The book contains the fundamentals of electronics and 40 tested circuits and their descriptions. Below is the list of projects:

1.Circuit Symbols & conventions
2.Basic Tools and Test Equipment

  • Hand tools
  • Multimeter
  • Logic Probe
  • Trimming tool set.

3.Soldering/de-soldering equipment

  • SOLDERING TIPS

4.Safety precaution for preventing electric shock
5.Ohm’s law
6.Fixed and Variable Resistors

  • Resistor Colour code and conventions
  • Naming Convention.
  • The E12 Range
  • The E24 Range
  • Simplifying The Color Code
  • Resistor wattage

7.Capacitors and capacitive reactance.

  • Colour coding and marking schemes for fixed capacitors
  • IEC letter and digit code for r & c values 
  • Conversion table for capacitance values

8.Inductors (coils) and inductive reactance
9.Circuit assembly

  • Breadboard.
  • Stripboard
  • Printed Circuit Board

10.Illustrations of some commonly used components

  • Tactile switch
  • Loudspeaker
  • Piezo Buzzer
  • Diodes
  • Light Emitting diode (LED)

7-Segment LED display

  • DIL/DIP switch
  • SIL/SIP RNW

11.Stabilized Power-supply
12. Versatile TTL/CMOS Logic and Clock Probe

Things which you can learn


*Applications of different ICs like CD4011, CD4001, NE555, op amp etc.
*Application LED, IR LED, Variable resistor and capacitor, inductor.
*Application of L14F1.
*Application of ultrasonic transmitter and receiver.
*Use of breadboard.
*Application of transistor as amplifier and switch.
*Use of different switches like DPDT, SPDT, SPST.
*Use of relay.

 

 

Automatic Low Power Emergency Light Save Rs. 250.00

Automatic Low Power Emergency Light

by KNS Pvt Ltd
Save Rs. 250.00
Rs. 1,000.00
Rs. 750.00

The automatic low power emergency light is a white LED based emergency light that offers the following advantages:

  1. It is extremely bright due to the use of white LEDs.
  2. The light turns ON automatically when mains supply fails and turns OFF when mains power resumes.
  3. It has its own battery charger. When the battery is fully charged, charging stops automatically.

No. of ICs used: 1

Learning from this project

  • Application of the adjustable voltage regulator IC LM317.
  • Application of Zener diodes for voltage regulation.
  • Application of diodes in the bridge arrangement for rectification.
  • Application of NPN and PNP transistors.

Product Description

Build yourself a cool automatic low power emergency light which can be used during a power failure. An added bonus is that it charges automatically.

Circuit operation

This automatic low power emergency light comprises of two sections: charger power supply and LED driver.

The charger power supply section is built around the 3-terminal adjustable voltage regulator IC LM317 (IC1), while the LED driver section is built around the transistor BD140 (T2).
In the charger power supply section, input AC mains is stepped down by transformer X1 to deliver 9V, 500 mA to the bridge rectifier comprising of four diodes (D1 through D4). A filter capacitor (C1) eliminates ripples.

Unregulated DC voltage is fed to input pin 3 of IC1 and provides charging current through a diode (D5) and a limiting resistor (R16). By adjusting the preset (VR1), the output voltage can be adjusted to deliver the required charging current. When the battery gets charged to 6.8V, zener diode (ZD1) conducts and charging current from regulator IC1 finds a path through the NPN transistor T1 (BC548) to ground and it stops charging the battery.

The LED driver section uses a total of twelve 10mm white LEDs. All the LEDs are connected in parallel with a 100-ohm resistor in series with each. The common-anode junction of all the twelve LEDs is connected to the collector of the PNP transistor BD140 (T2) and the emitter of this transistor is directly connected to the positive terminal of the 6V battery. The unregulated DC voltage, produced at the cathode junction of diodes D1 and D3, is fed to the base of transistor T2 through a 1-kilo-ohm resistor.

When mains power is available, the base of transistor T2 remains high and T2 does not conduct. Thus LEDs are off. On the other hand, when mains fails, the base of transistor T2 becomes low and it conducts. This makes all the LEDs (LED1 through LED12) glow. The mains power supply, when available, charges the battery and keeps the LEDs off as transistor T2 remains cut-off. During mains failure, the charging section stops working and the battery supply makes the LEDs glow.

Click To View Circuit Diagram

Click here to Download PDF

Hybrid Solar Charger Save Rs. 201.00
Rs. 2,750.00
Rs. 2,549.00

Hybrid Solar Charger

Hybrid Solar Charger

by KNS Pvt Ltd
Save Rs. 201.00
Rs. 2,750.00
Rs. 2,549.00

Summary

Working of the circuit is simple. When the output from the solar panel is 12 volts or more, zener diode ZD1 conducts and provides 11 volts to the inverting terminal of IC1. Since its non-inverting input gets a higher voltage at this time, the output of the comparator turns high and the same is indicated by glowing green LED1. Transistor T1 then conducts and relay RL1 energizes. Thus the battery gets charging current from the solar panel through the normally-open (N/O) and common contacts of relay RL1.

Learning

Things which you can learn:
1. Solar energy harvesting
2. Solar charging
3. application of relays
4. step-down transformer
5. Optimum battery charging

Product Description

Build a simple hybrid charger for your home/office so that it can automatically change the source for charging the battery, thus making sure that the battery charging is not affected by the clouds.

The efficiency of a solar charging system depends on the weather conditions. Usually, the solar panel gets four to five hours of bright sunlight in a day. If the weather is cloudy or rainy, it affects the charging process and the battery does not attain full charge. This simple hybrid solar charger can solve the problem as it can charge the battery using both solar power as well as AC mains supply. When the output from the solar panel is above 12 volts, the battery charges using the solar power. When the output drops below 12 volts, the battery charges through AC mains supply.

 

Click To View Circuit Diagram

 

Click here to Download PDF