Home » Archives for April 2011

Audio Light Modulator diagram

Saturday, April 30, 2011

Audio Light Modulator diagram

Audio light modulations add to the enjoyment of music in the course of functions organised at property or outdoors. Presented here is one such easy circuit in which light is modulated using a little fraction of the audio output from the speaker terminals of the audio amplifier. The output from the speaker terminals of audio amplifier is connected to a transformer (output transformer utilised in transistor radios) via a non-polarised capacitor. The use of transformer is vital for isolating the audio source from the circuit inside the sensitivity control potentiometer VR1 supplied within the input to transistor T1 might be adjusted to guarantee that conduction takes location only after the AF exceeds specific amplitude. This control has to be adjusted as per audio source level. The audio signal Proper earthing of the circuit is fairly crucial. The diode bridge provides pulsating DC output and acts as a guard circuit between the mains input and pulsating DC output. Extreme care is essential to stay away from any electric shock

Posted in: , | | |  

Running Message Display circuit diagram

Running Message Display circuit diagram

Light emitting diodes are advan- tageous due to their smaller size, low present consumption and catchy colours they emit. Here is really a running message display circuit wherein the letters formed by LED arrangement light up progressively. As soon as all the letters of the message have been lit up, the circuit gets reset. The circuit is built around Johnson decade counter CD4017BC (IC2). Among the IC CD4017BE’s features is its provision of ten fully decoded outputs, creating the IC ideal for use in a whole range of sequencing operations. In the circuit only one of the outputs remains high as well as the other outputs switch to high state successively on the arrival of each and every clock pulse. The timer NE555 (IC1) is wired as a 1Hz astable multivibrator which clocks the IC2 for sequencing operations. On reset, output pin three 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 therefore letter ‘W’ is illuminated. On arrival of initial clock pulse, pin three 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 every successive pulse, the other letters of the display are also illuminated and lastly the total word becomes visible. On the following clock pulse, pin 6 goes to logic 1 and resets the circuit, along with the sequence repeats itself. The frequency of sequencing operations is controlled with the assist of potmeter VR1.

Posted in: , | | |  

Flashy Christmas Lights

Flashy Christmas Lights

This simple and affordable circuit built about a well-liked CMOS hex inverter IC CD4069UB gives four sequential switching outputs that might be utilized to control 200 LEDs (50 LEDs per channel), driven directly from mains supply. Input supply of 230V AC is rectified by the bridge rectifiers D1 to D4. Soon after fullwave rectification, the average output voltage of about 6 volts is obtained across the filter comprising capacitor C1 and resistor R5. This supply energises IC CD4069UB. Flashy Christmas Lights
All gates (N1-N6) of the inverter have been utilised here. Gates N1 to N4 have been utilised to control four high voltage transistors T1 to T4 (2N3440 or 2N3439) which in turn drive four channels of 50 LEDs each and every via present limiting resistors of 10-kilo-o Base drive of transistors might be adjusted with the aid of 10-kilo-ohm pots supplied in their paths. Remaining two gates (N5 and N6) form a low frequency oscillator. The frequency of this oscillator could be changed by way of pot VR1. When pot VR1 is adjusted To get the top outcomes, a low leakage, very good high quality capacitor should be utilized for the timing capacitor C2

Posted in: | | |  

Optical toggle change utilizing an individual Chip

Optical toggle change utilizing an individual Chip

Making use of dual flip-flop IC CD4027 utilize a 555 centered monostable circuit to provide input clock pulses. The circuit explained here obviates this requirement. One of the two flip-flops inside of IC CD4027 alone acts as square wave shaper

Posted in: | | |  

Automated Dual output Display

Automated Dual output Display .This circuit lights up ten bulbs sequentially, 1st in one direc- tion and then within the opposite direction, thus presenting a nice visual impact. In this circuit, gates N1 and N2 form an oscillator. The output of this oscillator is employed as a clock for BCD up/down counter CD4510 (IC2). Depending on the logic state at its pin 10, the counter counts up or down. In the course of count up operation, pin 7 of IC2 outputs an active low pulse on reaching the ninth count. Similarly, during count-down operation, you again get a low-going pulse at pin 7. This terminal count output from pin 7, soon after inversion by gate N3, is connected to clock pin 14 of decade counter IC3 (CD4017) Automated Dual output Display . which is configured here as a toggle flip-flop by returning its Q2 output at pin 4 to reset pin 15. Thus output at pin 3 of IC3 goes to logic 1 and logic 0 state alternately at each and every terminal count of IC2. Initially, pin three (Q0) of IC3 is high as well as the counter is in count-up state. On reaching ninth count, pin three of IC3 goes low and as a result IC2 starts counting down. When the counter reaches 0 count, Q2 output of IC3 momentarily goes high to reset it, thus taking pin three to logic 1 state, as well as the cycle repeats. The BCD output of IC2 is connected to 1-of-10 decoder CD4028 (IC4). In the course of count-up operation of IC2, the outputs of IC4 go logic high sequentially from Q0 to Q9 and therefore trigger the triacs and lighting bulbs 1 through 10, 1 soon after the other. Thereafter, during count-down operation of IC2, the bulbs light within the reverse order, presenting a wonderful visual effect

Posted in: | | |  

Subscribe to: Posts (Atom)
My Zimbio
> TopOfBlogs .sg   TopOfBlogs