230V Led Flasher Circuit using DIAC

This is a very simple LED flasher circuit diagram that is powered from AC 230V mains. This Flasher can be used as a power indicator for the AC 230V mains supply. This circuit is made with few numbers of parts namely, a LED, two Resistors, one Capacitor, one Diode and one DIAC.  The DIAC act the main role to flashing the LED. DIAC is a bidirectional device. It conducts current only after its breakover voltage has been reached its threshold. Most DIACs break-over voltage is around 30 V.

230V Mains Power Indicator LED Flasher Circuit Diagram

Fig: Circuit Diagram of 230V Led Flasher

When mains is connect to the circuit, the Capacitor(C1) starts charging through Diode(D1) and Resistor(R1). When the voltage on the capacitor reached the DIAC’s threshold voltage, the DIAC get turn on. And LED gets Lights(flash). At the same time Capacitor(C1) goes discharges and breakover voltage of DIAC also decrease and LED turns OFF. The on off time of the LED depends on the value of Capacitor(C1)  and Resistor(R1).

Note that the flashing time of the LED shown in the animating figure is not the exact timing of ON/OFF.

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Buck Converter 1 Watt White LED Driver

This is an example of efficiently driving a 1 watt white LED from a 12 volt
 battery using a buck converter. The LED could simply be connected with a
 series resistor to get the desired current, but the efficiency would be
 only 25% since the resistor would drop 9 volts while the LED only requires
 3. The buck converter provides about 90% efficiency.

 The idea is to establish a circulating current through the inductor, diode
 and load, while the switch replenishes the lost load energy on each cycle.
 The duty cycle of the switch will be the output voltage divided by the input
 voltage, or about 3/12 (25%) in this case. Its actually a little greater
 since there is a small (2.2 ohm) resistor in series with the LED that drops
 about 0.5 volt, so the total load is about 3.7 volts and the duty cycle is
 around 31%. The circuit could also be used to charge AA batteries from a
 12 volt source with adjustment to the duty cycle.

 The driver section uses a CMOS hex inverter (CD4069) where two of the
 inverters form an oscillator with 31% duty cycle at about 11.5 Khz,
 or 66us off time, and 21uS on time for the MOSFET switch. The remaining 4
 inverters are used in parallel to provide additional drive current to
 the gate of the MOSFET. The duty cycle can be adjusted with either the
 15K or 20K resistors.

 The minimum inductor value was worked out from E = L * di/dt and a LED
 current of 250mA. The minimum value is where the current falls to 0 during
 the switch off time, or 66uS. The peak inductor current would then be twice
 the average or 500mA and the inductor will charge from 0 to 500mA in 21uS.
 So, di/dt is 0.5 /.000021 = 23810 amps per second. The inductor voltage
 (E) will be 12 minus the load voltage 3.7 or 8.3 volts and the minimum
 inductor value L will be 8.3 / 23810 = 0.35 mH. The actual value used should
 be somewhat higher to avoid the current falling to zero and to avoid large
 peak currents and possible saturation. The example here uses a approximate
 2 mH inductor so the change in current is about 100mA and the peak current
 is lower at about 300mA. The current waveform is shown in the LTspice
 picture below. Notice the current ramps from about 50mA below the average
 current to about 50mA above the average or about 100mA total change. The
 15 ohm resistor in the LTspice picture represents the LED plus a 2.2 ohm
 resistor. The MOSFET is represented by the SW (switch) component, and the
 drive circuit by the V3 symbol.

The inductor (pictured below) should be rated for saturation current of more than the peak current, or maybe 300mA in this case. The toroid inductor used is fairly large for the task measuring about 1.5 inches diameter with 20 turns of #18 wire. The core is conductive so it probably should be taped in case the wire insulation fails. The picture shows the naked core for illustration. A smaller core with an air gap could be used to avoid saturation, but would require more wire which would add to the losses due to the wire resistance. Another approach is to use a higher frequency so smaller inductors can be used. But this will add to losses since there would be more switching transitions per unit of time, which adds to the loss. The diode is a VSK330 schottky 3 amp variety for low loss, but most any 1 amp rectifier could be used with somewhat less efficiency. The IRFZ44 MOSFET is also an overkill rated at 50 amps max but very low on-resistance of only 28 milliohms. A much smaller device could be used, but I dont have the numbers. Note the circuit has no regulation, so the 12 volt input should be stable. If the battery voltage varies, the duty cycle and LED current should be set using the highest expected supply voltage.

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Simple 16 Stage Bi Directional LED Sequencer

The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders" (74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate can be adjusted with the 500K pot. Two additional Schmitt Trigger inverters are used as a SET/RESET latch to control the counting direction (up or down). Be sure to use the 74HC14 and not the 74HCT14, the 74HCT14 may not work due to the low TTL input trigger level. When the highest count is reached (1111) the low output at pin 7 sets the latch so that the UP/DOWN input to the counter goes low and causes the counter to begin decrementing.

When the lowest count is reached (0000) the latch is reset (high) so that the counter will begin incrementing on the next rising clock edge. The three lowest counter bits (Q0, Q1, Q2) are connected to both decoders in parallel and the highest bit Q3 is used to select the appropriate decoder. The circuit can be used to drive 12 volt/25 watt lamps with the addition of two transistors per lamp as shown below in the section below titled "Interfacing 5 volt CMOS to 12 volt loads"

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Motorcycle LED Lights Circuit

Motorcycle LED Lights series is so simple that it only uses a few components, but the results are very satisfactory. Power consumption is small enough 6 Volt course is suitable for your motorcycle.

The 555 circuit lower than is a flashing bicycle light powered with four C,D or else AA cells (6 volts). Two sets of 20 LEDs yearn for alternately glimmer by the side of approximately 4.7 cycles for every flash using RC morals publicized (4.7K pro R1, 150K for R2 and a 1uF capacitor). epoch intervals for the two lamps are in this area 107 milliseconds (T1, high LEDs) and 104 milliseconds (T2 junior LEDs). Two transistors are used to provide extra current away from the 200 mA limit of the 555 timer. A single LED is placed in vogue run with the center of the PNP transistor so with the aim of the inferior 20 LEDs ride inedible at what time the 555 output goes superior in the course of the T1 instance interval. The high output level of the 555 timer is 1.7 volts fewer than the supply voltage.

tallying the LED increases the accelerate voltage mandatory designed for the PNP transistor to a propos 2.7 volts so to the 1.7 volt difference from supply to the output is insufficient to turn on the transistor. both LED is supplied with about 20mA of current for a complete of 220mA. The circuit must labor with bonus LEDs up to about 40 used for both cluster, before 81 total. The circuit resolve too work with fewer LEDs so it possibly will come to pass assembled and tested with righteous 5 LEDs (two groups of two plus solitary) earlier than calculation the others.

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Car Parking Sensor circuit Using Infra Red LED

This circuit can be used for an assist in parking the car near the garage wall backing up Pls. LED D7 illuminates Pls bumper-wall distance is about 20 cm., D7 + D6 illuminate at about 10 cm. and D7 + D6 + D5 at about 6 cm. In this manner you are alerted Pls approaching too close to the wall.

Car Parking Sensor circuit

All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc.

Note:

• The infra-red Photo Diode D2, should be of the type incorporating an optical sunlight filter: these components appear in black plastic cases. Some of them resemble TO92 transistors: in this case, please note that the sensitive surface is the curved, not the flat one.
• Avoid sun or artificial light hitting directly D1 & D2.
• If your car has black bumpers, you can line-up the infra-red diodes with the (mostly white) license or number plate.
• It is wiser to place all the circuitry near the infra-red LEDs in a small box. The 3 signaling LEDs can be placed far from the main box at an height making them well visible by the car driver.
• The best setup is obtained bringing D2 nearer to D1 (without a reflecting object) until D5 illuminates; then moving it a bit until D5 is clearly off. Usually D1-D2 optimum distance lies in the range 1.5-3 cm.

List Component of Car Parking Sensor circuit:

R1 : 10K
R2,R5,R6,R9 : 1K
R3 : 33R
R4,R11 : 1M
R7 : 4K7
R8 : 1K5
R10,R12-R14 : 1K
C1,C4 : 1µF/63V
C2 : 47pF
C3,C5 : 100µF
D1 : Infra-red LED
D2 : Infra-red Photo Diode (see Notes)
D3,D4 : 1N4148
D5-7 : LEDs (Any color and size)
IC1 : NE555
IC2 : LM324
IC3 : LM7812 

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1 5Volt Led using 555 IC

1.5Volt Led using 555 IC

This LED circuit is powered only by the cell of 1.5 V with IC 555. The timer IC is used in astable mode similar to the double-circuit voltage, which is the step from 1.5V to about 2.5V. The frequency of the circuit is about 60 Hz and consumes very little left that is not a problem.

Part List:

R1- 39 kilo-ohms
R2- 100 kilo-ohms
R3-10 ohms but if no light or very dim, just short it
C1- 100nF
C2- 10nF
C3- 220uF electrolytic capacitor
C4- 100uF electrolytic capacitor
D1- preferably schotky diode but ordinary diode like 1N4001 will do
555- use the CMOS type 555
LED- red, yellow and other low power led (do not use white or blue)
1.5V- any 1.5V battery

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LED flasher Circuit using NE555

This is a LED flasher Circuit using NE555. This schema consumes more power, but its advantage is when you need a variable flash rate, like for strobe diagram. You can actually use this schema as a remote control for strobes that have a remote input. Of course, it has many other applications besides strobes.

• R1, R2, C1 and the supply voltage determine the flash rate. Using a regulated power supply will do much to insure a stable flash rate. For a variable flash rate, replace R1 with a 1 megohm pot in series with a 22k resistor.
• The duty cycle of the schema (the percentage of the time LED 1 is on to the time it is off during each cycle) is deterimed by the ratio of R1 to R2. If the value of R1 is low in relationship to R2, the duty cycle will be near 50 percent. If you use both LEDs, you will probably want a 50 percent duty cycle. On the other hand, if R2 is low compared to R1, the duty cycle will be less than 50 percent. This is useful to conserve battery life, or to produce a strobe type effect, when only LED1 is used.
• The NE555 timer chip can be damaged by reverse polarity voltage being applied to it. You can make the schema goof proof by placing a diode in series with one of the supply leads.
• The purpose of R3 and R4 is to limit current through the LEDs to the maximum they can handle (usually 20 milliamps). You should select the value of these according to the supply voltage. 470 ohms works well with a supply voltage of 9-12 volts. You will need to reduce the value for lower supply voltages.
• Rainbow Kits offers several kits to build the above schema. You can also order these kits from RadioShack.com. The Radio Shack catalog numbers (and web pages) are as follows: standard kit with two 5mm red LEDs, (990-0067), kit with two red, two green and two yellow 3mm LEDs, (990-0063), kit with jumbo green LEDs, (990-0048), kit with jumbo red LEDs, (990-0049). You can also buy all the parts to build the schema at your local Radio Shack store, including a schema board (276-159B).

I have built a miniature strobe schema as follows. Use a 250k pot in series with a 4.7k resistor for R1. The 4.7k resistor sets the upper flash rate limit. Use 2.2k for R2. That sets a really short duty cycle. For this schema, you dont use LED 2 or R4. For LED 1, I used a two Radio Shack white LEDs in series and no R-3. The schema runs on a 9 v battery.

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Simple 13 Color LED Rainbow Wiring diagram Schematic

Only a few years ago, the choice of LEDs was limited to IR, red, yellow, and green. The LED manufacturers have been busy extending the spectrum, and filling in the gaps. The latest generation of organic LEDs (OLEDs) has added some dazzling new colors to the spectrum. This schema uses a set of 13 differently colored LEDs to generate a full color spectrum. The photo does not fully represent the colors generated due to camera limitations. The real-world display is very eye-catching. If you want to "trick out" your PC, this schema is for you. Forget about those boring blue PC light displays.

Simple 13 Color LED Rainbow Circuit Diagram

Specifications:

• Operating Voltage: 6-12V DC
• Operating Current: 145ma at 12V DC

Theory:

The LM2940T-5.0 low dropout voltage regulator converts the 6-12V DC input power to regulated 5 Volts. It was chosen over a standard 7805 regulator so that the schema could maintain regulation while operating on a 6V battery. The 1N4001 diode protects the schema from reverse polarity, if a battery or power supply capable of generating over 1 amp is used, a 1 amp fuse should be installed between the supply and the schema. The 5 Volts is used to drive each of the LEDs through individual current limiting resistors.

The resistor values were determined experimentally for equal brightness. Values are given as examples only, different sources of LEDs will require different resistor values. Resistor selection turns out to be the most difficult part of the diagram construction. A 100 ohm resistor in series with a 1K pot could be used in place of each resistor if individual brightness adjustments are desired. The table below lists the LED colors and wavelengths.

LED Color Wavelength Description

Deep Red 700nm ---------

Red 660nm traditional red

Orange Red 635nm "high efficiency" red

Orange 623nm also called red orange

Amber 594nm ---------

Yellow 588nm & traditional yellow

Yellow Green 567nm traditional green

True Green 523mn --------

Cyan 501nm verde green, blue green

Aqua 495?nm ---------

Deep Blue 470nm ultra blue

Powder Blue 430nm first generation "powder blue"

Violet 410nm ---------

Construction:

The schema was built on a prototype perforated board with printed solder pads. The schemary is hand-wired on the back side of the board. Care should be taken when soldering to the LEDs, a clip-on heat sink should be used while soldering the leads. Care should be taken to avoid zapping the LEDs on the violet side of the spectrum, they are sensitive to static electricity. The schema board can be mounted on a piece of white hardboard, the white paint reflects the colors nicely.

Use:

Apply power to the schema and enjoy the colorful glow. Do not stare directly into the array at close range for extended periods, some of the LEDs are extremely bright.

Taking The Circuit Further:

The spectrum could be extended on both the IR and UV sides. A brief scan through the Mouser catalog indicates the availability of these IR wavelengths: 940nm 880nm, 875nm, 870nm, 850nm. UV LEDs at 400nm, 395nm and 380nm are also available. There are also many LED colors available with wavelengths between the 13 colors shown, the colors selected were chosen for an evenly spaced color spectrum.

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Easy LED Flasher Schematic

Here the schematic diagram of Easy LED Flasher schema:

Parts List:

R1 = 10M ohm R2 = 1K – 100K ohm R3 = 470 ohm C1 = 0.47μF – 10μF/25V

D1 = 1N914 Q1 = 2N3904 Q2 = 2N3906 Led = High Brightness Red LED

This schema will flash a bright or high-brightness red LED (5000+ mcd). Very good for fake car alarm or other attention getting device. Part values are not significant, test something else to start with from your junkbox.Certainly, the 470 ohm resistor (R3) determines the LEDs brightness and limits the current supply to around 20mA. R3 value of 390 ohm may also be applied as a save value.

If you decide to go using a green or yellow led, which take more current, you might want to change the 470 ohm with an suitable value. Flash speed is established by R2 and C1 and is roughly three time constants (3*R2*C1). R1 provides bias to Q1 which ought to be small enough not to saturate Q2 with the capacitor disconnected. When the schema doesnt oscillate, R1 may be very low or R2 too high. D1 allows for highter duty cycle operation and limits the feedback at the base of Q1 to -0.7 volts. D1 might be ommited for low supply power like 6 - 9V and low duy cycle operation.

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LM2901 LED bar graph meter

Several LED above and other components used to determine the signal amplifier, when in a state of high and low . If the signal received from the amplifier circuit is high then the LED lamp are lit up everything and more bright LED lamps, but otherwise if the received signal is low then the lights on only one or two , even absent or faint.

To use the circuit you can connec with the output amplifier or speaker output , if there is reinforcing the other in the amplifier , can be connected to the output.

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One LED Flashing Circuit

This is LED flashing schema Here I have used common IC LM3909.This schema operates with 3V power supply.After making two diagram like this you can build a multi vibrator schema.

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LED Multicolour Backlights Wiring diagram Schematic

This is a LED Multicolour Backlights Circuit Diagram. This schema comprises two parts: a string of 5mm high-intensity white LEDs connected in series and the schema wired around. IC CD4060 with an inbuilt oscillator. The IC is wired such that its outputs Q4, Q5 and Q6 are chosen for colour display. On power-’on’ reset, these outputs go ‘high’ simultaneously but for different time durations. The Q4 output goes ‘high’ for about 18 seconds, Q5 about 38 seconds and Q6 about 80 seconds. These outputs are connected to forty 5mm LEDs through transistors T1, T2 and T3.

It is necessary to boost the current because LEDs are connected in parallel. To do so, transistor BD135 is used. The 1.2-kilo-ohm base resistor prevents overloading of BD135. The 100-ohm resistor acts as the current limiter. Provide heat-sink to each BD135 transistor. LEDs of three colours—blue, orange and red—are used here.

LED Multicolour Backlights Circuit Diagram

 

Fig. 1: Circuit for multicolour curtain backlight

To reduce the time duration for which IC outputs go high, replace 2.2-mega-ohm resistor (R4) with 1 mega-ohm. Replace 2.2-mega-ohm resistor with 3.9 mega-ohms to increase the time duration. Power supply for the IC is provided by 220V AC to 9V, 1.5A step-down transformer after rectification and filtering.

A combination of different colours results due to switching on of transistors T1 through T3 for different time durations. These colours with a white background create a beautiful display. The first group of LEDs lights up a few seconds after power to the schema is switched ‘on.’

Fig. 2: Arrangement of LEDs

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PC Driven LED Display Wiring diagram Schematic

Here is a schema to generate sequentially running light effects using a simple program written in C. The output of the program is taken from the LPT port of a PC and then fed to the interfacing schema for the LED display. The outputs of the interfacing schema are decoded, inverted, and then connected to LEDs through optocouplers.

 Fig. 1: Interfacing schema for PC-driven LED display

The interfacing schema along with the 25-pin parallel port is shown in Fig. 1. IC1 (74LS138) is a high-speed 1-of-8 decoder/demultiplexer. In the schema, only five outputs (pins 10 through 14) of IC1 are used. These outputs are inverted using  NOT gate IC2 (7404). Optocouplers IC3 through IC7 (MCT2E) are used to prevent the schema from damage in the event of short schema in the load.  Thus the loads comprising LED blocks LB1 through LB5 are isolated from the interfacing schema including the PC. Each LED block contains a number of LEDs connected in series.

The LEDs can be arranged, for instance, to display a sequential running light and fountain pot as shown in Figs 2 and 3. The colour of LED blocks can be green and red alternately.

Fig. 2: LED block arrangement for sequentially running light   

 Fig. 3: LED block arrangement for fountain pot

The program can be compiled and run through Turbo C compiler. In the program, the function outport(p,x) is used, where ‘p’ is the address of the controller port and ‘x’ is the value sent to it. Here, controller port  LPT1 is used, whose base address is 378H. If LPT2 is to be used, the base address must be 278H. When the delay time delay() is increased, the running speed of LEDs decreases and vice versa.

In the schema, 100-ohm fixed resistors R6 through R10 can be replaced with 100-ohm or 200-ohm presets for decreasing and increasing the intensity of LEDs.

The program for LED display is as follows:

This schema costs around Rs 100.

Sourced By: EFY Electronics Author:  R. Karthick

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