Mutchus

Description  The LED flasher circuits below operate on a single 1.5 volt battery. The circuit on the upper right uses the popular LM3909 LED flasher IC and requires only a timing capacitor and LED. The top left circuit, designed by Andre De-Guerin illustrates using a 100uF capacitor to double the battery voltage to obtain 3 volts for the LED. Two sections of a 74HC04 hex inverter are used as a squarewave oscillator that establishes the flash rate while a third section is used as a buffer that charges the capacitor in series with a 470 ohm resistor while the buffer output is at +1.5 volts. When the buffer output switches to ground (zero volts) the charged capacitor is placed in series with the LED and the battery which supplies enough voltage to illuminate the LED. The LED current is approximately 3 mA, so a high brightness LED is recommended. In the other two circuits, the same voltage doubling principle is used with the addition of a transistor to allow the capacitor to discharge ...

An LED is usually a series resistor needed to ensure that the LED does not get too much power. The disadvantage of such a resistor is that the current thus also changes by the LED and the brightness as the voltage changes.  This circuit prevents that, by independent of the voltage, a constant current through the LED.The circuit uses two transistors and two resistors. The circuit can be connected to voltages of from 5 to 24 V.   Constant LED Power Supply Circuit Diagram

This white-LED driver circuit is ideal for use in a garden light. It automatically turns the LED on at night and runs from a single 1.2V nicad cell which is recharged by a solar cell during the day. The prototype used the existing casing and solar cell from an old garden light but you could also use a solar cell from a solar education kit. Diode D1 allows the solar cell to charge the battery during the day and prevents it from discharging back into the solar cell at night. Transistor Q1 controls the LED driver circuit. This transistor is normally on during the day (ie, when there is output from the solar cell) and so Q2 and the LED are off. At night time, Q1 is off and this allows a simple blocking oscillator circuit based on T1, R2 and Q2 to operate. This circuit in turn drives LED1 via a 1W resistor which limits the peak current into the LED. T1 is wound bifilar, with the two windings configured to produce a center-tapped winding. Winding AB is the main primary winding and winding BC...

This will flash a LED, employing a single 1.5v cell. it's going to even flash a white LED even supposing this kind of LED needs regarding three.2v to 3.6v for operation. The circuit takes regarding 2mA however produces a really bright flash. LED on 1.5v SUPPLY A red LED needs regarding one.7v before it'll begin to illuminate - below this voltage - NOTHING! This circuit takes regarding 12mA to illuminate a red LED employing a single cell, however the fascinating feature is that the approach the LED is illuminated. The 1u electrolytic may be thought of to be a 1v cell. (If you wish to be technical: it charges to regarding one.5v -0.2v loss as a result of collector-emitter = one.3v and a lost of about 0.2v via collector-emitter in diagram B.) It is firstly charged by the 100R resistor and therefore the third transistor (when it's totally turned ON via the 1k base resistor). this is often shown in diagram "A." throughout this time the second transistor isn't turne...

The author 'just wanted to do a bit of microcontroller programming'. However, the project rapidly grew into this impressive and visually attractive pyramid. The circuit consists essentially of a specially-sawn printed circuit board,  23 LEDs and a microcontroller. Despite the fact that the microcontroller  is a rather modest Atmel ATtiny2313, the author nevertheless has found room in the 2 KB flash memory for 16 different light sequences. The 23 LEDs are divided into three groups. The lower and middle sections consist of eight LEDs, while the upper section  has just seven. The microcontroller has only 20 pins, and so it is not feasible to provide a direct individual drive for each LED. The multiplexing approach adopted uses just eleven output port pins. Buffer transistors are used to increase the  current drive capability of each output. The software was written in assembler and can, as usual, be downloaded from the Elektor web pages accompanying this  article [1]  as eit...

Here i am going to present you a simple Emergency Light circuit diagram using 2 white Leds. Leds are convenient, cheap, cool and having long life. In this circuit we are using 2 Leds (white is prefered) to increase the brightness. The heart of this circuit consists of IC HEF 4093. The circuit is powered by a 9V battery. CIRCUIT DIAGRAM OF SIMPLE EMERGENCY LAMP/LIGHT COMPONENTS USED IN THE CIRCUIT IC HEF 4093 D 1N4001 R1 330KΩ R2 100Ω C 10μF Back To HOME For More

The LM3410 IC is a constant current LED driver useful in either boost con-verter or SEPIC design applications. A SEPIC (Single Ended Primary Induct-ance Conver ter) design allows the power supply’s output voltage to be set above, below or equal to its input voltage. In this application the chip is configured as a boost-converter (i.e. the output voltage is greater than the input voltage).  LM3410 LED Driver Circuit Diagram . The LM3410 is available in two fixed-frequency variants. Using either the 525 kHz or 1.6 MHz clock version it is possi-ble to build a ver y compact LED driver. The output stage can supply up to 2.8 A, allowing several high-power LED s to be driven from a rechargeable Lithium cell or several 1.5 V bat-teries. The chip also features a dimmer input giving simple PWM brightness control.Output current is defined by an external shunt resistor. To keep losses low the LM3410 uses an internal voltage reference of just 190 mV. Power dissipation in the shunt resistor...

Light Emitting Diode The LESD is basically a device which changes input electrical energy into output optical radiation in the visible or infrared position of spectrum depending on the semiconductor material used. LEDs have replaced incandesced lamp in many applications because of low voltage long life and fast on off switching. He materials used in manufacturing the LEDs are 1.        Gallium Arsenide Phosphide (GaAsP): It provides either red light or yellow light. 2.        Gallium Phosphide (GaP): It provides red or green light. 3.        Gallium Arsenide (GaAs): It provides infrared radiation Principle: When a P-N junction forward biased, charge carrier recombination take place at a junction as electron cross from the n- side and combine with holes on the p- side. Free electrons are in the conduction band of energy level while holes are in the valence band. Therefore electronics are at place ...

1. Chips Chips of LED strip lights include domestic ones, Taiwan-made chips, as well as imported chips(including chips from U.S., Japan, Germany, etc.). Different chips are labeled with different prices. The most expensive chips come from U.S., which is followed by Japan's and Germany's. Taiwan-made chips are affordable for many manufacturers. 2. Sealing There're 2 types of sealing, resin sealing and silicone sealing. The resin one is cheaper, but the thermal performance is a bit weak. The silicone one has good thermal performance while the price is more expensive. 3. LED Color Consistency Though currently there are a lot of packaging factory, but most of small packaging plants have no color separation machine. Thus it is difficult to control the quality. Without spectral separation of the LED, the color consistency would be poor. The light effect of LED strips is not so good. of course. the price difference will be relatively large. smd led strip 4. Soldering Effect There...

Signals when an on-circuit battery is exhausted 5V to 12V operating voltage A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED D1 flashes to attire the user's attention, signaling that the circuit is running, so it will not be left on by mistake. The circuit generates about two LED flashes per second, but the mean current drawing will be about 200µA. Transistors Q1 and Q2 are wired as an uncommon complementary astable multivibrator: both are off 99% of the time, saturating only when the LED illuminates, thus contributing to keep very low current consumption. Circuit diagram : Flashing-LED Battery-status Indicator Circuit Diagram The circuit will work with battery supply voltages in the 5 - 12V range and the LED flashing can be stopped at the desired battery voltage (comprised in the 4.8 - 9V value) by adjusting Trimmer R4. This range can be modified by changing R3 and/or R4 value slightly. When the batt...