Showing posts with label led. Show all posts
Showing posts with label led. Show all posts
Monday, August 5, 2013
Simple Solar LED Lantern
This solar LED lantern can be used as an emergency light. Its 6V battery can be charged either from 230V, 50Hz AC mains or a 12V, 10W solar panel. Two LED indicators have been provided—red LED (LED1) indicates battery charging and green LED (LED2) indicates fully-charged battery.
You can choose to charge the battery either from the mains power or the solar panel by using the single-pole, double-throw (SPDT) switch. Capacitor C1 (1000µF, 35V) removes ripples from the power supply and regulator IC LM7809 (IC1) provides regulated 9V DC to the emitter of pnp transistor T1 (TIP127/BD140) and pin 7 of op-amp IC CA3140 (IC2), which is configured in comparator mode.
The reference voltage of 6.3V at pin 2 of IC2 is obtained through the combination of resistor R7 (1-kilo-ohm) and zener diode ZD1 (6.3V). The comparator controls charging of the battery. Pin 3 of IC2 is connected to the positive terminal of the battery to be charged through resistor R5. When the battery is fully charged, it stops charging and the green LED (LED2) glows to indicate the full-charge status.
When the battery voltage is low, diode D1 (1N4007) forward-biases and the battery connects (through resistor R3) to the collector of T1 for charging (indicated by the glowing of red LED1). Three high-wattage white LEDs (LED3 through LED5), such as KLHP3433 from Kwality Photonics, are used for lighting. These are switched on using switch S3.
You can choose to charge the battery either from the mains power or the solar panel by using the single-pole, double-throw (SPDT) switch. Capacitor C1 (1000µF, 35V) removes ripples from the power supply and regulator IC LM7809 (IC1) provides regulated 9V DC to the emitter of pnp transistor T1 (TIP127/BD140) and pin 7 of op-amp IC CA3140 (IC2), which is configured in comparator mode.
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When the battery voltage is low, diode D1 (1N4007) forward-biases and the battery connects (through resistor R3) to the collector of T1 for charging (indicated by the glowing of red LED1). Three high-wattage white LEDs (LED3 through LED5), such as KLHP3433 from Kwality Photonics, are used for lighting. These are switched on using switch S3.
Tuesday, May 14, 2013
230 Blinking LED circuit
Note
# When you use Capacitors use more than 40V
# 230V is dangerous so this circuit is not good for kids.
This is wonderful circuit.Normally we can light up LEDs with 230v.But those are not blinking.This circuit shows how to make a blinking LED circuit.
Thursday, April 11, 2013
Simple LED Voltmeter
Four µ741 op-amps are used here to measure the voltage ranging from 3V to 12V DC. The voltage measured is displayed on eight LEDs.
The inverting inputs (pin 2) of IC1 through IC4 are supplied with regulated 12V DC through voltage dividers R1 through R4. So the inverting input of each op-amp forms the reference voltage. The non-inverting inputs (pin 3) of the op-amps are tied together and connected to the input terminals. The voltage to be meaured is fed to these input terminals.
When the input voltage exceeds the reference voltage of any of the op-amps, its output goes high, making the corresponding LEDs to glow.
This circuit is designed to measure 3V, 6V, 9V and 12V DC. For instance, when the input voltage is 3V, LED7 and LED8 glow. When the input voltage is 12V, all the LEDs glow.
Note. You can use a quad device such as LM324 instead of µ741 ICs.
Circuit Diagram:
The inverting inputs (pin 2) of IC1 through IC4 are supplied with regulated 12V DC through voltage dividers R1 through R4. So the inverting input of each op-amp forms the reference voltage. The non-inverting inputs (pin 3) of the op-amps are tied together and connected to the input terminals. The voltage to be meaured is fed to these input terminals.
When the input voltage exceeds the reference voltage of any of the op-amps, its output goes high, making the corresponding LEDs to glow.
This circuit is designed to measure 3V, 6V, 9V and 12V DC. For instance, when the input voltage is 3V, LED7 and LED8 glow. When the input voltage is 12V, all the LEDs glow.
Note. You can use a quad device such as LM324 instead of µ741 ICs.
Circuit Diagram:
Saturday, March 30, 2013
Converting a Dead CFL into an LED Tubelight Circuit Idea
You might have already read about this interesting idea in many different sites. Its about converting a dead CFL into a sleek LED tube light circuit. In this post we learn the procedures with more details.
How many times did you throw away a dead or over used faulty CFL unit into the dust bin? Well, we do this quite often whenever we find one of our home CFL lamps no longer illuminating or illuminating dimly.
You would be surprised to know that the circuit inside the lamp in fact never blows of or becomes weak. Its the tube portion which gets blackened, and unresponsive. It means the circuit of most of the discarded CFL units never goes faulty, and can be recycled through some other means.
For a layman this might look pretty tough....but actually its quite easy. The tube portion of the CFL may be simply replaced with LEDs, and reused for getting the same illumination that your previous CFL used to give... well almost the same.
Lets learn the procedures.
Find a dead CFL unit, and very carefully open up the lid which holds the tube from the lower cup type enclosure.
You must do this very carefully using a screwdriver equipment, making sure you dont damage the internal circuit while doing this.
If you find it difficult to insert the screwdriver end across the joint opening, use a fine hacksaw to make a small section of the opening wider by sawing it some. Now you can force open the lid by using the screwdriver.
This will immediately expose the internal circuit and the connections.
You will find the tube ends terminating with a pair of wires and connecting with the circuit board at four points arranged in a row through fine wire links. Cut these connections with a sniper so that the tube portion gets separated from the circuit board.
Join the above terminals from the ends so that only two terminals end up as the output.
Next using 4 nos 1N4007 diodes build a bridge rectifier, and connect it to the above terminals as shown in the diagram.
Now through a suitable holder and plug device connect the above system to mains and check the voltage a the output of the above connected rectifier.
It should be around 100 to 150 volts DC.
You have just transformed a dead CFL into a small transformerless power supply ideally suitable for illuminating LEDs (white).
Now comes the LED assembly part which may be constructed in the following manner:
To figure out the number of LEDs that would fit inside the output voltage of the above unit, we need to divide the measured voltage with 3.3V. Suppose the measured voltage was 120V, dividing this by 3.3 would give around 36 (numbers).
Use the derived number of LEDs and connect all of them in series with a 5 Ohm, 1/4 watt series resistor.
Done! Now simply connect the LED assembly end terminals with the bridge output of the modified CFL power supply.
You can test the system by providing mains supply to it....the LEDs should illuminate with dazzling light.
Now fix the assembly appropriately so that the CFL circuit gets inside its original holder while the LEDs may be integrated to the holder over a suitable rectangle type of box, or inside any other decorative cabinet as per user preference.
WARNING: THE IDEA IS BASED ON A SIMILAR CIRCUIT WHICH WAS PUBLISHED IN A DIFFERENT WEBSITE, IT HAS NOT BEEN VERIFIED BY THE AUTHOR.
THE CIRCUIT IS NOT ISOLATED FROM MAINS, AND THEREFORE IS EXTREMELY DANGEROUS IN UNCOVERED, POWERED POSITION.
How many times did you throw away a dead or over used faulty CFL unit into the dust bin? Well, we do this quite often whenever we find one of our home CFL lamps no longer illuminating or illuminating dimly.
You would be surprised to know that the circuit inside the lamp in fact never blows of or becomes weak. Its the tube portion which gets blackened, and unresponsive. It means the circuit of most of the discarded CFL units never goes faulty, and can be recycled through some other means.
For a layman this might look pretty tough....but actually its quite easy. The tube portion of the CFL may be simply replaced with LEDs, and reused for getting the same illumination that your previous CFL used to give... well almost the same.
Lets learn the procedures.
Find a dead CFL unit, and very carefully open up the lid which holds the tube from the lower cup type enclosure.
You must do this very carefully using a screwdriver equipment, making sure you dont damage the internal circuit while doing this.
If you find it difficult to insert the screwdriver end across the joint opening, use a fine hacksaw to make a small section of the opening wider by sawing it some. Now you can force open the lid by using the screwdriver.
This will immediately expose the internal circuit and the connections.
You will find the tube ends terminating with a pair of wires and connecting with the circuit board at four points arranged in a row through fine wire links. Cut these connections with a sniper so that the tube portion gets separated from the circuit board.
Join the above terminals from the ends so that only two terminals end up as the output.
Next using 4 nos 1N4007 diodes build a bridge rectifier, and connect it to the above terminals as shown in the diagram.
Now through a suitable holder and plug device connect the above system to mains and check the voltage a the output of the above connected rectifier.
It should be around 100 to 150 volts DC.
You have just transformed a dead CFL into a small transformerless power supply ideally suitable for illuminating LEDs (white).
Now comes the LED assembly part which may be constructed in the following manner:
To figure out the number of LEDs that would fit inside the output voltage of the above unit, we need to divide the measured voltage with 3.3V. Suppose the measured voltage was 120V, dividing this by 3.3 would give around 36 (numbers).
Use the derived number of LEDs and connect all of them in series with a 5 Ohm, 1/4 watt series resistor.
Done! Now simply connect the LED assembly end terminals with the bridge output of the modified CFL power supply.
You can test the system by providing mains supply to it....the LEDs should illuminate with dazzling light.
Now fix the assembly appropriately so that the CFL circuit gets inside its original holder while the LEDs may be integrated to the holder over a suitable rectangle type of box, or inside any other decorative cabinet as per user preference.
WARNING: THE IDEA IS BASED ON A SIMILAR CIRCUIT WHICH WAS PUBLISHED IN A DIFFERENT WEBSITE, IT HAS NOT BEEN VERIFIED BY THE AUTHOR.
THE CIRCUIT IS NOT ISOLATED FROM MAINS, AND THEREFORE IS EXTREMELY DANGEROUS IN UNCOVERED, POWERED POSITION.
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