DS

For a lower parts count than the 2 transistor multivibrators, 2 LED s can be alternately flashed with a 555 integrated circuit configured as shown in Schematic 2.  I chose the combination of a 2K2 and a 47K resistor to determine the oscillation frequency along with the 10 uF capacitor connected to pins 2 and 6. You can practically change the (R Speed) 47K value to between 10K and 100K or more. Greater resistance = lower speed. You may also wish to connect up a 100K or so potentiometer instead of the 47K resistor for a variable speed version. Additionally, the 10 uF capacitor value can be changed. Feel free to experiment. Although, alternately flashing LED s  is great for the beginner to electronics, the basic one ON, one OFF circuit gets boring quickly. In the next section, we will try to improve the look and try to approximate a flash like a police car (within limits).

This is a unique flasher circuit employing a single driver transistor that takes its flash-rate from a flashing LED. The flasher within the photo is 3mm. An ordinary LED won't work. The flash rate can not be altered by the brightness of the high-bright white LED will be adjusted by altering the 1k resistor across the 100u electrolytic to 4k7 or 10k. The 1k resistor discharges the 100u in order that when the transistor activates, the charging current into the 100u illuminates the white LED. If a 10k discharge resistor is used, the 100u isn't absolutely discharged and therefore the LED doesn't flash as bright. All the components within the photo are within the same places as within the circuit diagram to make it simple to envision how the components are connected. The circuit uses a flashing LED to flash a super-bright 20,000mcd white LED

This circuit was designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and negative supply. Especially suited for car or panel pilot lights, this device can drive lamps up to 10W. Circuit diagram : Two-wire Lamp Flasher Circuit Diagram Parts: R1_____6K8  1/4W Resistor R2_____270K   1/4W Resistor R3_____22K   1/4W Resistor C1_____220µF   25V Electrolytic Capacitor C2_____10µF   25V Electrolytic Capacitor D1_____1N4002  100V 1A Diode Q1_____BC557   45V 100mA PNP Transistor Q2_____BD139   80V 1.5A NPN Transistor LP1_____Existing filament Lamp: any type in the range 3-24V 10W max. SW1_____Existing On-Off switch B1_____Existing V DC source: any type in the range 3-24V suited to the lamp adopted Notes: Break lamp(s) to negative supply connection(s), then insert the circuit between existing lamp(s) connection(s) and negative supply (respecting polarities!). C1 value can be varied from 100 to 1000µF ...

Introduction The LM3909 is an integrated circuit (IC) which will flash a light-emitting diode (LED). Using only two extra components and a battery, the circuit is cheap and has a very low current drain from a 1.5 V cell. The circuit can be used as a novelty flasher, an indicator for a dummy alarm bell box, or it could be attached to a torch so that it could be found easily in the dark! The simple circuit Led Flasher with the LM3909 IC Diagram Assembly The circuit can be built on a small piece of Veroboard (the piece shown in Figure 2 measures 15 holes by 10 strips). Using such a board, follow these instructions. 1. Depending on how far away you want the LED from the circuit board, solder a length of insulated wire to each lead of the LED. Use different colours of insulation – say, red and black, connecting the red lead to the anode (a) lead (the longer one) of the LED, and the black one to the cathode (k). Figure 2 shows these leads. 2. Cut the copper tracks as shown i...

This circuit operates with 230v.you can use this circuit to decorate your parties.I think this will be a wonderful circuit to you all.This circuit was taken from my old circuit book called 100 circuit book.Here DIAC ER 900 and Triac BTW 11-400. 230 V Flasher Circuit diagram Note: Be careful when you deal with 230V Build this circuit on a PCB Use only mentioned values.  Sourced By: Freecircuitsdiagram4u

This two LED flasher circuit uses any DC supply from 3V to 12V. Flash rate is controlled by R1,C1 and R2,C2. Larger values create slower fash rates, smaller values higher flash rates.

This Simple Solar Flasher circuit is a single transistor fly back (Joule Thief) circuit that features a third coil. With it, flash duration and brightness is much enhanced, without resorting to large value capacitors. Simple Solar Flasher  Circuit Diagram:

Ordinary LED flashers turn the LED on and off abruptly, which can get a little irritating after a while. Circuit diagram : Simple Smooth Flasher Circuit Diagram The circuit shown here is  more gentle on the eyes: the light intensity changes very slowly and sinusoidally, helping to generate a relaxed mood. The circuit shows a phase-shift oscillator with an adjustable current source at its out-put. The circuit is capable of driving two LEDs in series without affecting the current. The frequency is set by three RC networks, each of which consists of a 100 µF capacitor and a 22 kΩ resistor. Operation is largely independent of supply voltage, and the average LED current is set at about 10 mA. The circuit adjusts the voltage across the emitter resistor so that it matches the base voltage of the first transistor (around 0.6 V). The phase shifting network gives rise to the oscillation around this average value. In the prototype of this circuit we used an ultra-bright red LED. Author : B...

This Simple Solar Flasher circuit is a single transistor fly back (Joule Thief) circuit that features a third coil. With it, flash duration and brightness is much enhanced, without resorting to large value capacitors. Circuit Diagram:

Flashing neon globes have use in many applications, however their relatively high working voltage precludes their general use where a mains supply is not available . This simple neon tube flasher circuit enables neon tubes or bulbs to be operated from a low voltage dc supply. The voltage required to ignite the neon tube is obtained by using an ordinary filament transformer (240-6.3Vl in reverse . Battery drain is quite low  being in the region of 1 to 2 milliamps for a nine volt battery. O1 is a unijunction transistor and operates as a relaxation oscillator. its frequency of operation is determined by R2-C1.  The pulses from Q1 are directed to O2 which in tum drives O3 into saturation. The sharp rise in current through the 6.3V winding of the transformer as 03 goes into saturation induces a high voltage in the secondary winding causing the neon to flash.  The diode D1 protects the transistor from high voltage spikes generated when switching currents in the transformer...

This circuit alternately flashes 2 white LEDs, on a 3v supply and produces a really bright flash. The circuit produces a voltage above 5v if the LED isn't in circuit however the LED limits the voltage to its characteristic voltage of three.2v to 3.6v.   The circuit takes concerning 2mA and is actually a voltage-doubler (voltage incrementer) arrangement. The 1k charges the 100u and therefore the diode drops zero.6v to prevent the LED from setting out to illuminate on 3v. When a transistor conducts, the collector pulls the 100u down towards the 0v rail and therefore the negative of the electro is actually concerning 2v below the 0v rail. The LED sees 3v + 2v and illuminates terribly brightly when the voltage reaches about 3.4v.  All the energy within the electro is pumped into the LED to supply a really bright flash. DUAL 1v5 WHITE LED FLASHER This circuit alternately flashes 2 white LEDs, on a 1.5v supply and produces a really bright flash. The circuit produces a voltage o...

This circuit alternately flashes 2 white LEDs, on a 3v supply and produces a really bright flash. The circuit produces a voltage above 5v if the LED isn't in circuit however the LED limits the voltage to its characteristic voltage of three.2v to 3.6v.   The circuit takes concerning 2mA and is actually a voltage-doubler (voltage incrementer) arrangement. The 1k charges the 100u and therefore the diode drops zero.6v to prevent the LED from setting out to illuminate on 3v. When a transistor conducts, the collector pulls the 100u down towards the 0v rail and therefore the negative of the electro is actually concerning 2v below the 0v rail. The LED sees 3v + 2v and illuminates terribly brightly when the voltage reaches about 3.4v.  All the energy within the electro is pumped into the LED to supply a really bright flash. DUAL 1v5 WHITE LED FLASHER This circuit alternately flashes 2 white LEDs, on a 1.5v supply and produces a really bright flash. The circuit produces a voltage o...

Many battery powered devices use two AA alkaline cells.  Often you will not know when it is time to replace the batteries until the device powered by them actually stops operating.  The hobby circuit below can be connected to a 3v battery, to give you some warning when the battery is nearing its end of life. It will flash a LED when the battery voltage drops to about 2.4 volts. The electronic circuit draws only 1ua of current in standby mode and jumps to only 20ua when flashing, so it can safely be included without depleting the battery energy. A voltage detector IC from Panasonic (Microchip also makes similar devices) is used to monitor the battery voltage. The device’s open drain output swings low, when the battery voltage is below 2.4 to 2.5 volts. This action turns on the two transistor oscillator circuit, which drives the LED with short current pulses lasting only 2ms. Source: DiscoverCircuits