Showing posts with label led. Show all posts
Showing posts with label led. Show all posts
Wednesday, 12 June 2013
Pin Led Light
Tuesday, 28 May 2013
1 5V LED Flasher Circuit Diagram
This is so simple circuit diagram.you can power this circuit with 1.5V power supply.To get maximum results please build this on a PCB
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Thursday, 2 May 2013
Dimmable White LED Lamp
Nowadays you can buy white LEDs, which emit quite a bit of light. They are so bright that you shouldn’t look directly at them. They are still expensive, but that is bound to change. You can make a very good solid-state pocket torch using a few of these white LEDs.
The 12V DC input voltage is routed through the 1A fuse and the on/off switch. The 1N4001 diode acts as a crowbar device. If reverse polarity is applied, the fuse will blow and the rest of the circuitry will be protected. Power is sent to the LM2941CT voltage regulator IC. The regulator is wired to produce a voltage range from 5.5V (dim) to 8.3V (bright).
The 4.7K resistor across the 1K brightness adjustment potentiometer produces a non-linear brightness adjustment to compensate for the eyes logarithmic brightness perception response. The LEDs are organized in six series groups of three with a 24 ohm current limiting resistor on each group. This arrangement limits the maximum current through each LED group to around 20mA.
Connect the DC input terminals to a 12V source, such as a 12V lead acid battery. Be sure to observe the correct polarity. Turn the power switch on and adjust the brightness adjustment for the desired brightness. Parts
- 1X LM2941CT low-dropout voltage regulator
- 1X aluminum heat sink
- 1X 1A DC rated fuse
- 1X DC switch
- 1X 1N4001 diode
- 2X 1K 1/4W resistors
- 2X 4.7K 1/4W resistors
- 6X 24 ohm 1/4W resistors
- 1X 1K linear potentiometer
- 18X 5mm white LEDs, 20mA max
- 1X 22uF 16V electrolytic capacitor
- 1X 100nF 25V monoblock capacitor
Wednesday, 27 March 2013
How to Make a LED Chaser cum Blinker Circuit Using IC 4017
The presented circuit was requested by Mr.Joe, one of the keen followers of this blog. The circuit initially was intended to be used for generating LED strobe light effects and was asked to be modified such that it could be used as an LED sequencer as well as a blinker. The change over would be implemented via a toggle switch.
The circuit diagram may be understood with the following points:
The IC 4017 is not new to us and we all know how versatile and competent this device is. Basically the IC a Johnson’s decade counter/divide by 10 IC, fundamentally used in applications where sequencing positive output signals are required or desired.
The sequencing or the orderly shifting of the outputs take place in response to a clock pulse that needs to be applied at the clock input pin #14 of the IC.
With every rising positive edge of the clock input, the IC responds and pushes its output’s positive from the existing pin out to the next pin out in the order.
Here a couple of NOT gates are used as a oscillator for providing the above clock pulses to the IC 4017. VR1 may be adjuted for determining or fixing the speed of the sequencing.
The outputs of the IC are connected to an array of LEDs in a specific order which makes the LEDs look like as if they are running or chasing during the operations.
If the circuit would be required only to produce the chasing effect, the diodes would not be required, however as per the present ask the diodes become important and allows the circuit to be used as a blinker also, depending upon the position of the switch S1.
When the switch S1 is positioned at A, the circuit behaves like a light chaser and produces the normal chasing effect over the LEDs which start illuminating in sequence from top to the bottom, repeating the operations as long as the circuit remains powered.
As soon as S1 is flicked toward B, the clock signals from the oscillator are shifted into the input of the transistor T1, which instantly stats to pulsate all the LEDs together in response to the received clocks from N1/N2 configuration.
Thus as per the requirement we have successfully modified an ordinary light chaser circuit with an additional feature through which the circuit now is also able to function as a LED flasher.
Do not forget to connect the inputs of the remaining unused gates from the IC 4049 either to the positive or the negative of the supply. The supply pins of the IC 4049 also need to be connected to the relevant supply rails of the circuit, kindly refer to the datasheet of the IC.
Tf all the ten outputs of the IC 4017 are required to be integrated with LED sequencing, just connect pin #15 of the IC to ground and use the left over outputs of the IC for the required sequencing of the LEDs in the order of: 3,2,4,7,10,1,5,6,9,11
Parts List
The fooliwng parts will be needed for making this LED light chaser cum flaher circuit:
R1, R2, R3 = 1K,
VR1 = 100K linear pot.
All LED resistors are = 470 Ohms,
All diodes are = 1N4148,
All LEDs = RED, 5mm or as per choice,
T1 = 2N2907, or 8550 or 187,
C1 = 10uF/25V
C2 = 0.1uF,
IC1 = 4017,
N1, N2 = IC4049
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