In the CD4094 data are synchronized on the rising edge and the LCD display will take on the falling edge shows us that this signal can be shared.

Well, then at the rising edge CD4094 transfers the data of the new byte out and fall on the side of the LCD display reads. Keep in mind that this method can not read LCD information display.

Now comes the hard part: How to separate text commands. LCD has a pin for this: RS pin. When this command for 0 accepted, as accepted in a text (ASCII characters). How do you solve this?

Before sending a character to initialize a timer on CD4094 500uSec. The resistor R1 will load capacitor C5. Then send the character to the CD4094 as quickly as possible. Thus, the capacitor simply does not have enough time to discharge. The LCD display will accept it as text. In order to command is the same, only in reverse. The capacitor has to be discharge.

Emitter follower T1 formed to protect the network R / C. The reason for this is that the LCD RS input is a TTL input signal and we put it to work quite well.

Program C Language

#include <hidef.h>
#include "derivative.h"

#define LINE1    0x80
#define LINE2    0xC0

#define DTASHT   0x01     // PTA0
#define CLKSHT   0x02     // PTA1
#define STBSHT   0x04     // PTA2

#define CTRL     1
#define DATA     0

void Shift(char, char);
void Delay(int);
void Write(char, char*);
void Init_Dsp(void);

void main(void) {

CONFIG1 = 0x01;
CONFIG2 = 0x00;

DDRA    = 0x07;
PTA     = 0x00;

Init_Dsp();

for(;;) {
Init_Dsp();
Write(LINE1,"  Hola Mundo    ");
}
}

//=====================================

void Init_Dsp(void) {
PTA |= CLKSHT;
Shift(CTRL,0x06);
Shift(CTRL,0x0E);
Shift(CTRL,0x38);
Shift(CTRL,0x80);
Shift(CTRL,0x0C);     // Cursor off
Shift(CTRL,0x01);     // Clear Display
}

void Write(char pos, char *text) {
Shift(CTRL,pos);
while(*text) Shift(DATA,*text++);
}

void Shift(char donde, char dato) {
int i;

for(i=0; i<8; i++){
if(dato & 0x80) PTA |=  DTASHT;
else            PTA &= ~DTASHT;

if(donde) {
PTA &= ~CLKSHT;
Delay(200);
PTA |=  CLKSHT;
}
else {
PTA &= ~CLKSHT;
PTA |=  CLKSHT;
}
dato <<= 1;
}
PTA |=  STBSHT;
PTA &= ~STBSHT;
if(donde) Delay(2000);
}

void Delay(int time) {
for(; time>0; time--);
}

In the example given in Figure 3, A2 anode is alternately positive and negative, while the trigger is negative (pulling power) when the transistor is conducting.
By observing the table, we say that the triac operates in quadrants 2 and 3. Different combinations can be obtained. It should just point out that Mode 4 should be avoided, due to excessive consumption in the range above 100 mA against only 50 mAin modes 1, 2 and 3 for a triac type ’standard’.
Indeed there is a model called ”sensitive”, which require low gate currents of 5 to 10 mA. This is important because the intensity of the load must be greater from the intensity of the trigger, and that is why dimmer on Trade found, in addition to the indication of the maximum load, minimum load indication, if not triac does not work anymore.
The principle is that the triac is initiated after a control pulse to the next zero crossing of the wave field. The command can be impulsive and Figure 4 provides such a circuit, which is much less demanding than the continuous control of Figure 3.

This type of circuit can then be powered by an RC network from transformer if the control circuit does not consume too much. A level 0 on input C blocks the triac.
The power output is maximum in this case since the triac is initiated immediately afterthe zero crossing of the AC voltage, but we can intervene in different ways for each control pulse delay in order to vary the intensity applied to the load.

A simple way to achieve this is an RC network like Figure 5. The offset depends on the values ​​of these two components R and may vary. The diac trigger placed on the phase shift results in a more importantly, it does lead that when the voltage reaches 30V.

There are, however, other more sophisticated ways to obtain complete phase shifts (180°) and automatic systems for modulating the intensity according to various phenomenasuch as light or temperature.

Figure 6a and 6b show the power applied to the function of the load in the delay from the relative control pulse to zero.

The main drawback of this type of setting is easily lead noise and especially on the receptor MW / LW.

These can be partly eliminated by the addition of a LC circuit comprising a network asthat of FIG 7, wherein the two capacitors (optional) are provided for alternatingnecessarily class (X2) and to self calibrated depending on the intensity required.

This assembly is suitable for circuit ”dimmer”, but if you want to just use a triac switch is better to use a special circuit in the control of the zero wave sector.
These include for example an opto-triac OMC 3041 with ”zero crossing” is planned forthis application and the pinout is shown in Figure 8.
Moreover, the isolation of a optotriac, some 7,500 V, and the control current of ten milliamperes give safety and ease of use highly significant for switching loads of several amperes at a voltage of 230 V or more.
Don’t forget that mounting a TRIAC, with or without a power transformer, if they are not equipped with optotriacs or similar devices are connected directly to the mains and which should be very cautious with this kind of circuit.
Figure 9 shows a universal interface for controlling various devices connected to the mains using, for example, a computer.

The control is effected by applying a positive level of the LED, the opto-triac in turn controls a triac that there will be chosen according to the respective load. We can equipthe suppression of this interface in Figure 7.In some cases, particularly if the load is highly inductive, it may be necessary to add a protection circuit. Figure 10 shows an effective way to protect the triac.

Finally, we must not forget to equip each of its triac sink if the power involved requires it,usually you start to place a radiator from a 100 W power for conventional models 6/8 A.Be aware that there are triacs provided for a current of 40A.
To end this article, Figure 11 shows you a very simple TRIAC scheme is however sufficient, allowing you to remove the doubt about how each of your triacs.

A diode for reverse polarity protection
Of course, there is a polarized connector system such as the hollow plug. For many small self-built circuits, voltage circuits for testing, often taken from the power supply. And because it can happen that you accidentally turn on the power supply with the wrong polarity on the circuit, which makes your project vain. Even when soldering hollow connectors can happen the same.

For circuits with such errors can not be avoided, but is there any simple protection? yes, with the installation of the polarity protection diode in the positive supply voltage of the circuit!

Diodes mounted so that the anode is connected to the positive terminal ofvoltage source and the cathode to the positive terminal of the circuit. If thecircuit is connected to the correct polarity, the current flows from thepositive terminal through the diode in the circuit and the negative terminalback to a voltage source.

If the circuit is accidentally connected to wrong polarity (the positive voltage to the negative terminal of the circuit), no current can flow because it flows in the ”wrong” direction (this will be blocked by diode).

When installing a protection diode we must consider two things :

• Diode should be able to cope current consumption of the circuit.
• In the diode voltage drop of about 0.7 volts, ie, the circuit gets about 0.7volts less than the applied voltage.

There are also speakers that can reproduce only a limited frequency range and are optimized for this then. Woofer has a large membrane and reproducing low frequencies (bass) optimized for high performance. Tweeter is optimized for reproducing of high frequencies (treble), which works with small diaphragms which work better than the large ones. Then there are the midrange speaker, which are optimized for medium-frequency.

Some speakers are integrated in a hi fi box, which are optimized for specific frequency ranges and produce only this, for example, a low, midrange and tweeter. In most cases the crossover is used, consists of different filters, which only allow the speaker to receive the frequency with which they can process. Since high and in the midrange compared to the woofers are too loud, is made at the crossover for this level adjustment with resistors, as is seen in the example circuit shown below.

During the manufacture of hi-fi speakers will be more things to consider. The most important thing in this case, known as Thiele Small parameters. With this, for example, the correct case size specified of woofer. But this is a specialized field that is not discussed further here. There are a lot of literature!

A loudspeaker is a device that converts low-frequency electrical signals into sound. The task of the speaker is to enable the air in periodic oscillations – which in turn brings in the human ear drum to vibrate.

To convert the electrical signals into sound waves are displaced almost exclusively membranes into mechanical vibrations, which also gets the air to the membrane in motion. These membranes will normally act as a piston radiator, ie that the entire membrane is moved smoothly.

This is generally only – in relation to the membrane surface – to reach low frequencies. All membranes are divided into regions at higher frequencies which move in opposite directions, thereby arise naturally dead lines on which does not move the diaphragm. These phenomena are called partial vibrations.

There are different types of speakers such as the full-range speaker, Dome, Piezo speakers or horns. We will turn our attention here only to the full-range speaker, because it is often used.

Structure and Function

Speaker can be driven in various ways. Most common are the electrodynamic loudspeaker. It includes an annular permanent magnet in its center a freely movable coil, also called voice coil (spule). This voice coil is directly connected to the diaphragm.

Structure of an electrodynamic loudspeaker

If the alternating voltage applied to the voice coil, magnetic field generated in the voice coil. Depending on the direction of the magnetic field, the voice coil is repelled by the permanent magnet (the voice coil moves out of the permanent magnet) or attracted (the voice coil moves into the permanent magnets). Provided that the oscillation is transmitted in a frequency range of human ears, We perceive this as a tone or sound.

Speakers still have a polarity. Normally, this is such that the voice coil moves out of the permanent magnet. If the speaker is installed incorrectly, it swings to “wrong side”, that is backwards, which at high volume levels, can cause very strong vibrations, the diaphragm will strikes the rear, which can result in damage to your speakers. Therefore, we must pay attention to polarity when connecting speakers

Loudspeaker Impedance
Each speaker has a certain resistance, known as impedance. With a resistive impedance is meant, which is only available with an alternating voltage. Typical impedance values ​​for today’s speakers are 4 or 8 ohms. Older speakers may also have a higher impedance.

Fuse Characteristics and usage
Fuses are available in various lengths and diameters. European standard size is 5 x 20 mm, in the U.S. there are 6.3 x 32 mm, which corresponds to 1/4 x 1 1/4 inch. Sometimes appear some special sizes but this is very rare.

Fuses are available in different trigger speed rates, how fast fuse is triggered in case of overcurrent:

The American types, from 6.3 x 32 mm have a different trigger conduct than European types! Fast types not tolerate inrush current exceeds the nominal value of the fuse. To secure equipment with high input currents such as transformers, is better with a a slow or medium time lag fuses, if the fuse is located at the transformer primary side.

In principle, this should have a fuse box when it assembled in an electronic device! For installation of the fuse, there are different types of fuse holders. There are those that can be directly soldered onto a circuit board for tightening. However, it should always open the case to replace a fuse in it. It’s more comfortable with a fuse holder, which can be externally screw from the outside. For the internal fuse box, there is a cover to prevent accidental contact.

Inside a high-pressure sodium vapor lamp is a discharge vessel (burner), which consists of transparent alumina ceramics. The discharge vessel is filled with sodium and another noble gas. To protect and isolate thermally burner and some thick metal cable is pressed into balls or elliptical-shaped glass tube. Metal wires are also used to supply electricity. If the light is in operation, the temperature in the discharge vessel of about 1,000 ° C and pressure of the gas is very high, because of this they are named.

High pressure sodium vapor lamps are usually manufactured with the bases E-27, E-33 or E-40. These lamps must be operated with a ballast and an ignitor that provides the necessary starting voltage of about 3,000 to 5,000 volts. After ignition, the lights will initially weak. Only after about 15 minutes, they reach full brightness.

High pressure sodium vapor lamps emit a very wide range spectrum of light. The color is yellow but over-emphasized. Common performance are 35, 50, 70, 100, 150, 250, 400, 700 and 1000 watts. Also, there are lamps with frosted glass bodies.

The mercury vapor high-pressure lamp contains a discharge tube made ​​of quartz (burner) that is associated with mercury and argon gas filled. The burner contains an ignition electrode, so that these lamps require a ballast operation only. The ignition takes place directly at the mains voltage of 230 volts.

The output light from mercury vapor lamps is about 3 times as lighter as the incandescent lamp, here is about 30-60 lm / W. The average lifespan is about 6 times greater, it is around 6000 hours. Without phosphorus on the inside of the glass spheres are light bluish-white color. Mercury vapor lamps require 3-5 minutes of heating, process re-ignition is possible only after cooling.

After startup process it barely lit first. Only when a certain quantity of mercury is vaporized and increasing the gas pressure in the burner, it will be brighter. Available in 50, 80, 125, 250, 400 and 700 watts.

Mercury vapor lamps Application
Mercury vapor lamps are used primarily for street lighting or floodlighting of sports fields and stadiums. Also for the illumination of churches, castles or large buildings, they are used.

Mercury vapor lamps Circuit
To limit the current in the circuit requires the lamp ballast. By this measure the power factor cos is reduced to about 0.5.

Compact fluorescent lamps or energy saving lamps have over regular bulbs for the same light efficiency a significantly lower power consumption – nearly 80 percent! Comparison between light bulbs and energy saving lamps is shown in the following table:

In addition, CFLs contain an electronic ballast which increases the operating frequency of the lamp to about 35 KHz. Due to this high frequency, the light is absolutely quiet and flicker-free. The lifetime of compact fluorescent lamps is much higher – they light about 8,000 to 10,000 hours, and therefore about 8 times longer than a normal light bulb! Nevertheless, there are also differences in the quality of compact fluorescent lamps! Cheap lamps generally produce a very cold light, which is often perceived as unpleasant. Here you need take up even better products, a pleasant and warm light to generate even have several years of warranty! Even today, compact fluorescent lamps are often surrounded by pear-shaped glass bulb,which the light bulbs are quite similar.

Decomposed energy-saving lamp

Each energy saving lamp contains an electronic ballast. This is located in the base of the lamp. It generates the necessary voltage for the lamp. Since this is at high voltage, it must be treated with caution:

Never operate an opened energy saving lamp! Only open old unused lamps, which are no longer operated.

Compact fluorescent lamps with G23 base

In addition to the compact fluorescent lamps with screw bases with which it also called the G23 pin base. These lamps contain only the case with a conventional starter and ballast (choke) operation, which is located mostly in the power cord plug. The lamps themselves are U-shaped and can only in special versions (which contain the ballast) or be used in special space provided lights, containing the ballast plug in the power cord.

Fluorescent lamps Design and function
Fluorescent lamps are one of the gas discharge lamp. It consists of a glass tube, which with mercury vapor and an inert gas such as argon or krypton filled. The inside of the glass tube coated with phosphor. This converts the light generated in the operation of the ultraviolet light in a longer wavelength, ie, into visible light.

The lamp has two electrodes made of tungsten. By a short voltage pulse, the gas is ionized and therefore electrically conductive. To generate this ignition voltage, a ballast is required. Conventional control gear (CCG) consist of a choke coil and a starter. The starter consists of a neon lamp and bimetal. Parallel to the starter, a capacitor is connected to the radio interference suppression.

The ballast is connected in series with the fluorescent lamp. Parallel to the lamp is the starter. When switching a small current from the ballast flows through the first electrode of the lamp by the starter to the second electrode of the lamp and from there to the N-conductor. It comes to glow in the neon lamp to the starter. This heats the bimetal and which close to the neon lamp is shorted and goes out. Now, a high current from the ballast flows through the electrode of the lamp by the starter to the N-conductor. Due to the high current builds in the choke coil of the ballast to a magnetic field. Simultaneously by the high power of the lamp electrodes are heated. Electrons out from it.

Since the shorted glow lamp is not lit in the starter to cool the bimetal again – they open up again and the circuit is interrupted. This interruption of current flow causes a collapse of the magnetic field in the ballast. The collapsing magnetic field generated by the self-inductance of the choke coil a voltage surge of nearly 1000 volts. This high voltage is applied to the electrodes of the lamp and accelerates the electrons in the lamp at high speeds – the gas electrically conductive and light the lamp.

This usually runs from ignition process several times until it comes to a stable ignition. Therefore, fluorescent lamps flicker when turning several times until they light up. Since the ballast is an inductive resistor in the ground, this also has a power consumption which is around 10 watts. We must therefore not only the power of the fluorescent lamp to see solely, but must also add to the ballast! Nevertheless, the power consumption is significantly lower than the same light bulb!

A disadvantage of an individually-operated fluorescent lamp, is that it flickers to the rhythm of the line frequency of 50 Hz. Therefore, fluorescent lamps lamps are often offered as a double with two tubes in so-called double switch. This, the second lamp has a capacitive ballast. This leads to a phase shift of 180 degrees between two lamps, which cancels the flicker.

Today, apart from the conventional control gear(CCG), there are also electronic control gear (ECG). It is much more expensive, but it has several advantages:

• Soft in the lighting
• Low power dissipation
• With high-frequency operation, no blinking lights
• There is no reactive power compensation required

Finally, note:

Never broke a fluorescent light! Glass tube containing a small amount of mercury which toxic! Therefore, this lamp in any case should not disposed in the trash, but should be brought to the collection!