•  
  •  

Running Message Display

Light emitting diodes are advan- tageous due to their smaller size, low current consumption and catchy colours they emit. Here is a running message display circuit wherein the letters formed by LED arrangement light up progressively. Once all the letters of the message have been lit up, the circuit gets reset. The circuit is built around Johnson decade counter CD4017BC (IC2). One of the IC CD4017BE?s features is its provision of ten fully decoded outputs, making the IC ideal for use in a whole range of sequencing operations. In the circuit only one of the outputs remains high and the other outputs switch to high state successively on the arrival of each clock pulse. The timer NE555 (IC1) is wired as a 1Hz astable multivibrator which clocks the IC2 for sequencing operations. On reset, output pin 3 goes high and drives transistor T7 to ?on? state. The output of transistor T7 is connected to letter ?W? of the LED word array (all LEDs of letter array are connected in parallel) and thus letter ?W? is illuminated. On arrival of first clock pulse, pin 3 goes low and pin 2 goes high. Transistor T6 conducts and letter ?E? lights up. The preceding letter ?W? also remains lighted because of forward biasing of transistor T7 via diode D21. In a similar fashion, on the arrival of each successive pulse, the other letters of the display are also illuminated and finally the complete word becomes visible. On the following clock pulse, pin 6 goes to logic 1 and resets the circuit, and the sequence repeats itself. The frequency of sequencing operations is controlled with the help of potmeter VR1.

The display can be fixed on a veroboard of suitable size and connected to ground of a common supply (of 6V to 9V) while the anodes of LEDs are to be connected to emitters of transistors T1 through T7 as shown in the circuit. The above circuit is very versatile and can be wired with a large number of LEDs to make an LED fashion jewellery of any design. With two circuits connected in a similar fashion, multiplexing of LEDs can be done to give a moving display effect

If there are any problems please contact webmaster@electronic-circuits-diagrams.com

Please share & like


Implement Whisker Switch  picture

Implement Whisker Switch

$50.00



8Pcs Cabinet Lamp Switch Black Closet Light Switch Automatic Door Switch Ward picture

8Pcs Cabinet Lamp Switch Black Closet Light Switch Automatic Door Switch Ward

$23.58



Vertical Float Switch: Sump Accessory -  picture

Vertical Float Switch: Sump Accessory -

$17.99



ELECTRIC COOLING FAN GROUND-ING THERMO-STAT SWITCH RADIATOR TEMP-ERATURE SENSOR picture

ELECTRIC COOLING FAN GROUND-ING THERMO-STAT SWITCH RADIATOR TEMP-ERATURE SENSOR

$17.99



Modern Sporting Ambidextrous Safety Selector Switch picture

Modern Sporting Ambidextrous Safety Selector Switch

$21.50



Foot Pedal Switch Pneumatic Foot Pedal Valve Kit, Foot Switch, 3 Way 2 Position picture

Foot Pedal Switch Pneumatic Foot Pedal Valve Kit, Foot Switch, 3 Way 2 Position

$16.99



POWERSTAT 3PN116C Variable Transformer Fused Switch Autotransformer 120V  variac picture

POWERSTAT 3PN116C Variable Transformer Fused Switch Autotransformer 120V variac

$85.00



Generator Transfer Switch picture

Generator Transfer Switch

$22.74



1/4

1/4" NPT Foot Pedal Operated Control Valve Air Pneumatic Switch 5 Way 2 Position

$44.00



Flotect Flow Switch for Hazardous Locations V4SS2U picture

Flotect Flow Switch for Hazardous Locations V4SS2U

$250.00