Published:2013/3/4 21:47:00 Author:Ecco | Keyword: DRIVING MANY LEDS
The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply. The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series.
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Published:2013/3/4 21:43:00 Author:Ecco | Keyword: DRIVING A BI-COLOUR LED
Some 3-leaded LEDs produce red and green. This circuit alternatelyflashes a red/green bi-coloured LED: (View)
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Published:2013/3/4 21:30:00 Author:Ecco | Keyword: BI-POLAR LED DRIVER
Some 2-leaded LEDs produce red and green. These are called Bi-polar LEDs. This circuit alternatelyflashes a red/green bi-polar LED:
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Published:2013/3/4 21:21:00 Author:Ecco | Keyword: 3x3x3, LED Cube
This circuit drives a 3x3x3 cube consisting of 27 white LEDs. The 4020 IC is a 14 stage binary counter and we have used 9 outputs. Each output drives 3 white LEDs in series and we have omitted a dropper resistor as the chip can only deliver a maximum of 15mA per output. The 4020 produces 512 different patterns before the sequence repeats and you have to build the project to see the effects it produces on the 3D cube.
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Published:2013/3/1 2:43:00 Author:Ecco | Keyword: LED, serial , LED digital tube, static display, common anode
LED- serial LED digital tube static display circuit (common anode ) is shown as figure.
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Published:2013/3/1 2:42:00 Author:Ecco | Keyword: LED , serial, LED digital tube , static display , common cathode
LED - serial LED digital tube static display circuit ( common cathode ) is shown as figure.
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Published:2013/2/27 20:26:00 Author:muriel | Keyword: Basic, LM3909, Led Flasher
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Published:2013/2/24 21:17:00 Author:muriel | Keyword: Automatic Emergency Light
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Published:2013/2/24 21:16:00 Author:muriel | Keyword: Main , Fuse-Panel, Emergency Light
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Published:2013/2/24 21:00:00 Author:muriel | Keyword: Incandescent Lamp Flasher
Incandescent Lamp Flasher using two IRF511 HexFets which are configured as a simple astable multivibrator to alternately switch the two lamps, La1 and La2, on and off. The R & C values given set the flash rate to about 1/3 Hz. By varying either the resistor or capacitor values almost any flash rate can be obtainded. Increase either C1 and C2, or R1 and R2, and the flash rate slows. Decrease them and the rate increases.Unlike most semiconductor devices, the power MosFet can be paralleled, without special current-sharing components, to control larger load currents. That can be an important feature when the device is used to turn on incandescent lamps, because the lamp's cold resistance is much lower than the normal operating resistance.A typical #1815 12 to 14-volt lamp measures 6 ohms cold. When 12 volts is applied, the initial current drawn is 2 amps. The same lamp, when operating at 12 volts, requires only about 200mA. The hot resistance figures out to be ten times its cold resistance, or 60 ohms. That tidbit should be considered when picking any semiconductor device to control an incandescent lamp. (View)
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Published:2013/2/20 1:00:00 Author:Ecco | Keyword: Laser diode driver , double broadband, transconductance , operational amplifier
The circuit has a pair of laser -emitting diodes and laser receiver diodes, constituting the reflection laser transmitter and receiver circuits, the figure mainly shows a laser emitting driving circuit.
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Published:2013/2/19 20:12:00 Author:muriel | Keyword: main fuse-panel, emergency lights
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Published:2013/2/19 20:10:00 Author:muriel | Keyword: Emergency Lights
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Published:2013/2/19 20:10:00 Author:muriel | Keyword: Emergency Lights
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Published:2013/2/19 20:09:00 Author:muriel | Keyword: Low cost, Automatic , Emergency Light
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Published:2013/2/19 20:05:00 Author:muriel | Keyword: Backup Lamp
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Published:2013/2/17 20:42:00 Author:Ecco | Keyword: Light control, energy-saving lamp
The working principle of the circuit is shown as figure, it is composed of the photoelectric conversion part, NAND gate, differential circuit and control circuit. When there is light, the photosensitive diode VD1 gets conduction, the potential of point A reaches the NAND gate YF1 door level, the output terminal of point b shows low potential, YF2 outputs the high potential, C1 and R5 form a differential circuit which outputs positive spikes at the point C, so BG1 gets conduction, J1 is instantaneously pulled ( then release ). Normally closed contact J1-1 is disconnected, CJ1 loses power and releases, the self-protection contact CJ1-1 disconnects, then the light is off.
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Published:2013/1/30 21:12:00 Author:muriel | Keyword: SPI Interface, Big, 7-Seg LED
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Published:2013/1/30 21:07:00 Author:muriel | Keyword: Interfacing Alphanumeric LCD
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Published:2013/1/29 1:41:00 Author:muriel | Keyword: Sine wave display, Nokia 3310 , LCD
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