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5 Lamp / LED Flash Driver

Mon, 08/10/2009 - 18:43 — vip

Description : General Description of the following circuit. This circuit is based around HT–2050 manufactured by HOLTEK semiconductors. It is a low cost, low-power C-MOS LSI designed for lamp andLED flash driver.


Volt meter circuit using LED

Mon, 07/27/2009 - 06:27 — vip

Description : This is a very useful circuit which when installed on your car gives the voltage of you car battery in a LED dot display form.The circuit is based on four comparators made of quad op amp LM324.The inverting inputs of IC are kept at at reference voltages 5.6V,5.2V,4.8V,4.4V respectively at pins 2,6,9,13 by resistors ,R3,R4,R5,R6.The battery voltage is directly fed to the nin inverting input throug the volatge divider arrangement using R1 and R7.When there is variation in the input supply the out put of each op amp goes high accordingly as they are wired as voltage comparators.T


LED Chaser

Thu, 07/23/2009 - 09:18 — vip

I don't know why, but people like blinking lights. You see LED chasers everywhere, in TV shows (Knight Rider), movies, and store windows. This schematic is my version of a simple 10 LED chaser. There is no 555 timer used because at my local electronics store they are over $4 Cdn. Instead, an oscillator made up of two sections of a 4011 NAND gate is employed. This chip is very inexpensive and extremely common.

Circuit diagram


Black Light

Thu, 07/23/2009 - 09:16 — vip

This circuit is a simple ultraviolate light that can be powered by a 6 volt battery or power supply that is capable of supplying 1 or more amps.

Circuit diagram


12VDC Fluorescent Lamp Driver

Thu, 07/23/2009 - 09:12 — vip

A number of people have been unable to find the transformer needed for the Black Light project, so I looked around to see if I could find a fluorescent lamp driver that does not require any special components. I finally found one in Electronics Now. Here it is. It uses a normal 120 to 6V stepdown transformer in reverse to step 12V to about 350V to drive a lamp without the need to warm the filaments.

Circuit diagram


LED or Lamp Flasher

Thu, 07/23/2009 - 08:21 — vip

Minimum parts counting

Designed for 3V battery operation

Parts:


Six-LED Bar Power Indicator

Mon, 07/20/2009 - 03:15 — vip

Useful to monitor audio power delivered to loudspeakers

No power supply - no setup required

Parts:

R1_____________220R  1/2W Resistor
R2,R5,R6,R8____100R  1/4W Resistors
R10,R12,R14____100R  1/4W Resistors
R3_____________220R  1/4W Resistor
R4,R7__________330R  1/2W Resistors
R9_____________560R  1/2W Resistor
R11____________820R  1/2W Resistor
R13______________1K2 1/2W Resistor

D1___________1N4004  400V 1A Diode
D2,D4,D6__BZX79C2V7  2.7V 500mW Zener Diodes
D3,D5,D7,D8,D9,D10   Red LEDs (Any dimension and shape) (See Notes)

40 LED Bicycle Light

Sun, 07/19/2009 - 13:40 — vip

The 555 circuit below is a flashing bicycle light powered with four C,D or AA cells (6 volts). Two sets of 20 LEDs will alternately flash at approximately 4.7 cycles per second using RC values shown (4.7K for R1, 150K for R2 and a 1uF capacitor). Time intervals for the two lamps are about 107 milliseconds (T1, upper LEDs) and 104 milliseconds (T2 lower LEDs). Two transistors are used to provide additional current beyond the 200 mA limit of the 555 timer.


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