Diagram Diagosis

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Friday, April 12, 2013

Simple Rain Alarm or Water Detector Circuit with SCR 106CY

Rain detector circuit may also be utilized to the challenge or any other pastime, rnwhich is so easy principles.When it rains plate (sensor) will receive rnrain. And a faithful work has paid to SCR1 and go with the flow preserve watch over Buzzer rnnoise.
Electronic Part List

R1 1K 1/4 W Resistor
R2 680 Ohm 1/4 W Resistor
D1 1N4001 Silicon Diode
BZ1 12V Buzzer
S1 SPST Switch
SCR1 C106B1 SCR 106CY
SENSOR See

Notes

Thern sensor is a small piece of PC board etched to the pattern showen in thern schematic. The hints must be very shut to every other, however with the aid of no indicates rntouching. A big spiral pattern would additionally work. 2. Make sure to make use of arn loud buzzer

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Thursday, April 11, 2013

11 W Stereo or 22 W Mono Power Amp

Integrated AF power amps have seen great improvements in recent years offering improved power and easier use. The TDA1519C from Philips contains two power amplifiers providing 11 W per channel stereo or 22 W mono when the two channels are connected in a bridge conﬁguration. The special in-line SIL9P package outline allows the chip to be conveniently bolted to a suitable heatsink. The TDA1519CSP is the SMD version, in this case the heat sink is mounted over, and in contact with, the top surface of the chip.

11W Stereo Amplifier Circuit Diagram

The operating voltage of this device is from +6V to +17.5V. The two channels of the amplifier are different in that one channel, between pins 1 and 4, is a non-inverting amplifier, while the other between pins 9 and 6 is an inverting amplifier. It is therefore necessary in stereo operation, to wire the speakers so that one of them has its polarity reversed. Each amplifier has an input impedance of 60kΩ and a voltage gain of 40dB, i.e. 100 times. When both amplifier are used in a bridge conﬁguration, the inputs are in parallel so that the input impedance will be 30kΩ.

22W Stereo Amplifier Circuit Diagram

A combined mute/standby function is provided on pin 8. In its simplest form this can be connected to the positive rail via a switch. When the switch is open the amplifier will be in standby mode and current consumption is less than 100µA. When the switch is closed, the amplifier will be operational. A circuit is also shown that uses the mute input to prevent the annoying switch-on plop heard when power amps are ﬁrst switched on This is caused by the rush of current to charge capacitors C1 and C2.

Mute/Standby Switch Circuit Diagram

The circuit shown generates a ramp voltage, which is applied to pin 8. At switch on, as the voltage rises from 3.3 V to 6.4 V, the amplifier will switch out of standby mode and into mute mode allowing C1 and C2 to charge. Only when the ramp voltage on pin 8 reaches 8.5V will the amplifier switch into active mode. Protection built into the TDA1519C would seem to make it almost foolproof. The two outputs can be shorted to either of the supply rails and to each other. A thermal shutdown will prevent overloading and the power supply input is protected against accidental reversal of the supply leads up to 6V.

Author : G. Kleine - Copyright : Elektor Electronics

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Tuesday, April 9, 2013

Making a Thermocouple or a Pyrometer

To make a furnace temperature meter, the sensing element is required to be particularly robust so that it is able to withstand the extreme high temperatures generally developed in furnaces and ovens. The circuit of a pyrometer explained here is based on a thermocouple principle which can be used to read high temperatures directly from the furnace or similar high temperature sources.

The article explains a straightforward concept which is being incorporated since very long for measuring high temperatures as in furnaces and ovens. Circuit design is enclosed herein.

A furnace as we all know is a device or a chamber where temperatures at very high levels are generated. Furnaces can be of many different types, ranging from the ones which are used in homes to the industrial types which are fundamentally associated with processing of metals, alloys, ores etc.

The furnaces used in houses (also called boilers) are only associated with raising the temperature of the interior to suitable levels and are therefore does not involve critical temperature levels for the required purpose. However with industrial furnaces, if the temperature level tends to falter might result in serious consequences and cause damage to the processed output. Therefore, the temperature inside these furnaces needs to be monitored through some suitable means, preferably through electronics.

In the year 1821 researcher Thomas Johann Seebeck observed that when two dissimilar metals are merged or joined at their ends to form two opposite junctions and when one of the junctions is heated while the other is cooled, current starts flowing through the system. This was confirmed by placing a compass near one of the above metals which produced deflections during the process.

The phenomenon was also later on researched and named after the respective scientists as the Peltier and Thomson effect.

The following examples will explain how the phenomena takes place:

Consider two dissimilar metals, copper and aluminum. Let the metals be formed into loops and joined at their ends by twisting as shown in the figure. Now as explained above suppose one of the junctions is heated, keeping the other junction at room temperature, the flow of current can be simply confirmed by introducing a milli ammeter anywhere in series with the “circuit” or as shown in the diagram.

However, the ammeter only determines and measures the flow of current and if we want to measure the voltage or the potential difference across the wiring we will have to use a voltmeter or rather a Milli voltmeter and connect it as given in the following diagram.

Here we can see that the second junction of the above circuit has been opened and the resulting terminals are configured with the voltmeter terminals.

The above directions and principles looks pretty straightforward and an easy alternative for measuring high temperatures. However, the system as one big drawback, since the entire phenomena is working and based on the temperature differences of the respective junctions, means that the introduction of any further junctions would directly affect and interfere with the actual readings of the system.

When we connect the meter terminals to the above explained thermocouple ends, the connections individually act as two more junctions, infusing two more temperature sensing points, which may either add up or deduct the readings from the actual sensing happening at the other end.

But having said that, the conditions can be rectified by keeping the meter connections as short as possible. It means that if the meter wires are kept absolutely small or in other words if the meter is directly connected across the thermocouple ends can make the differences negligibly small and can be ignored.

Though this principle is usually avoided and the problem is rectified by balancing out the disturbance through a Wheatstone bridge network. However with our experiment, in order to keep the complications to the minimum, we can make the proposed temperature meter by integrating the thermocouple links directly to the meter termination points.

We employ a rather unusual but very effective method of selecting long bars of the two dissimilar metals, which will help us to isolate the meter from the furnace heat to a safe distance and yet produce reasonably accurate reading of the measured temperature

The following explanation will illustrate the whole procedure to you:

You will require the following materials for making the discussed furnace temperature meter:

Copper and Aluminum sticks – 2 and a half feet long each, half centimeter in diameter.

Ammeter – 1 mA, FSD, moving coil type meter.

Wooden block with handles, drilled appropriately with through holes for reinforcing the metal rods.

The following procedure explains how to make a thermocouple or a pyrometer.

Procedure:

Using a sand paper clean of the metal rods gently so that any carbon or corrosion layers are scraped of, and the metals are made shining clean.

Using a pair of nose pliers, carefully bend the metals at certain angle (as illustrated in the diagram) and twist the ends firmly with the pliers.

At this state the rods will be in a quite vulnerable situation and will need to be reinforced at the free ends, so that the junction doesn’t disintegrate.

It is done by guiding the rods gently across the holes of a well dimensioned wooden block; the drilling must be selected such that the rods go snugly through them.

The meter now can be appropriately fixed over the wooden block itself and the rod ends also connected to the meter terminals.

Since the attached meter is an ammeter, will require an appropriately calculated resistor across its terminals, so the voltage across it may be translated into a readable potential difference or a voltage corresponding directly to the temperature sensed at the extreme end of the thermocouple.

The meter scale will also need to be calibrated linearly as per the corresponding temperature indications.

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