Siren circuit on the k155la3 chip. Siren diagram and connection

Every radio amateur has a k155la3 chip somewhere “littered around”. But often they cannot find a serious application for them, since in many books and magazines there are only schemes for flashing lights, toys, etc. with this detail. This article will consider circuits using the k155la3 chip.
First, consider the characteristics of the radio component.
1. The most important thing is nutrition. It is supplied to 7 (-) and 14 (+) legs and amounts to 4.5 - 5 V. More than 5.5 V should not be applied to the microcircuit (it starts to overheat and burns out).
2. Next, you need to determine the purpose of the part. It consists of 4 elements, 2 and not (two inputs). That is, if you apply 1 to one input and 0 to the other, then the output will be 1.
3. Consider the pinout of the microcircuit:

To simplify the diagram, separate elements of the part are depicted on it:

4. Consider the location of the legs relative to the key:

It is necessary to solder the microcircuit very carefully, without heating it (you can burn it).

Here are the circuits using the k155la3 chip:

1. Voltage stabilizer (can be used as a phone charger from the car's cigarette lighter).
Here is the diagram:


Up to 23 volts can be applied to the input. Instead of the P213 transistor, you can put a KT814, but then you have to install a radiator, since it can overheat under heavy load.
Printed circuit board:

Another option for a voltage stabilizer (powerful):


2. Car battery charge indicator.
Here is the diagram:

3. Tester of any transistors.
Here is the diagram:

Instead of diodes D9, you can put d18, d10.
Buttons SA1 and SA2 have switches for testing forward and reverse transistors.

4. Two options for the rodent repeller.
Here is the first diagram:


C1 - 2200 uF, C2 - 4.7 uF, C3 - 47 - 100 uF, R1-R2 - 430 Ohm, R3 - 1 kohm, V1 - KT315, V2 - KT361. You can also put transistors of the MP series. Dynamic head - 8 ... 10 ohms. Power supply 5V.

Second option:

C1 - 2200 uF, C2 - 4.7 uF, C3 - 47 - 200 uF, R1-R2 - 430 Ohm, R3 - 1 kohm, R4 - 4.7 ohm, R5 - 220 Ohm, V1 - KT361 (MP 26, MP 42, kt 203, etc.), V2 - GT404 (KT815, KT817), V3 - GT402 (KT814, KT816, P213). Dynamic head 8...10 ohm.
Power supply 5V.

Unprofitable neighborhood - rats, mice, moles, shrews, ground squirrels, "kitties", chipmunks, bears.

Various types of rodents bring us a lot of losses, troubles, and sometimes diseases. This is an undesirable neighborhood that we strive to get rid of in various ways - we spend money on the purchase of poisons, traps, traps, chemicals, biological products, etc. but our efforts are often in vain.

Agree, when you take care of the plants, you see how they grow, bloom ... and "THEY" come, what to do?

There are many ways to control rodents. In this article we will talk about a newer and safer, and in terms of money and economical method of dealing with our smaller “friends”.

An important discovery was the discovery of the hostility of rodents to high-frequency sounds (ultrasound), which are not heard by an ordinary person, and low-frequency sounds propagating in the ground. Electronic devices emitting these frequencies are safe for people, pets and birds, underground insects do not cause interference in the operation of the body and radio equipment.

I want to present you a series of concepts for repelling rodents. (1 - underground rodents, 2 - rats, mice, etc.)

1. Underground rodents (moles, shrews, bears)
They are known to use their heightened hearing to pick up the vibrations of the ground. The vibration of the soil warns rodents of danger and forces them to flee. We can use this fact.

It is enough to create a sound vibration in the soil with a frequency of 100 to 400 Hz. As a radiator, you can use a speaker from an old low-power receiver. The emitter is buried to a depth of 30 - 50 cm in the ground.

Let's start with the simplest devices. For their manufacture, the most common parts are used.

Option number 1
You can use an audio multivibrator on P-N-P or N-P-N transistors. With a supply voltage of 4.5 - 9 V, its power is sufficient to propagate the signal to 300 - 1000 m2. The disadvantage of this design is the constant work. Theoretically, the signal should come in periods and you will have to turn the multivibrator on and off from time to time.

When using the listed parts, the signal frequency is about 200 Hz. Speaker B1 - 0.25 W or 0.5 W.

Rice. one.
R1, R4 - 1 com; R2, R3 - 39 com; R5 - 510 ohm; C1, C2, C3 - 0.1 uF; V1, V2 - MP 26 or MP42; V3 - GT 402, GT403.

Rice. 2.
R1, R4 - 1 com; R2, R3 - 39 com; R5 - 1com; C1, C2, C3 - 0.1 uF; V1,V2 - KT315; V3 - KT815

Option number 2
As I noted above, the signal must be emitted periodically, so we emit the movements of the earth's layers as before an earthquake. This can be achieved using two multivibrators, one of which emits the signal we need, the second controls the operation of the first multivibrator. As a result, we will hear “beep-pause-beep-pause, etc.” from the speaker. The schematic diagram is shown in Fig.3.


Rice. 3.
Details: Rp - 100kom; R1, R4, R6, R9 - 1 com; R2, R3 - 47 com; R7, R8 - 27 com; R5, R10 - 510 ohm; C1, C2, - 500 uF; C3, C4 - 0.22 uF; C5 - 0.1 uF; V1, V2, V4, V5 - MP 26 or MP42; V3, V6 - KT 814, KT 816; VD1, VD2 - AL 307; B1 - 0.5 or 1 W with a resistance of 8 ohms.

Let's consider how the electronic "stuffing" of the repeller in Fig. 3 works. The device is based on multivibrators. One of them on transistors V4 and V5 generate oscillations with a frequency of about 200 Hz. Transistor V6 - amplifies the power of these oscillations. As can be seen from the diagram, the multivibrator on transistors V4, V5, V6 is the load of the right arm of the multivibrator assembled on transistors V1, V2, V3. Thus, power is supplied to this multivibrator at the moment when transistors V2, V3 are open. At this time, the resistance of their emitter-collector sections is very small, and the emitters of transistors V4, V5 and V6 are practically connected to the positive terminal of the supply source. When transistors V2,V3 are closed, the multivibrator does not generate. In other words, the device on transistors V1, V2 and V3 plays the role of an automatic power switch for a multivibrator on transistors V4, V5, V6. The variable resistor Rp serves to change the length of the pauses. LEDs VD1, VD2 - used for visual indication of "work-pause" modes. Any low-power transistors can be used in the repeller, for example, the MP series of the p-n-p structure, KT 361, KT 203, KT3107, etc. The KT 816 transistor can be replaced with GT402, GT403, P201, P214, etc. As a power source, you can use solar panels, two 3336 type batteries connected in series or from a mains power supply with an output voltage of 4.5 - 9 V. This device starts working immediately and does not require additional settings.

Option number 3
An underground rodent repeller can be assembled on a very common K155LA3 chip using an intermittent signal generator circuit.

And to amplify the sound, use a push-pull transformerless power amplifier as shown in Fig. 4.1a and 4.1b or using an audio transformer from low-power receivers as shown in fig. 4.2 The supply voltage of the repellers is 4.5 - 5V. The principle of operation of the intermittent signal generator is similar to the device described in option No. 2. It also contains two generators, one of which generates the frequency of the sound signal we need, it is assembled on the LE AND-NOT DD1.3 DD1.4, the second controls the operation of the first and is assembled on the LE AND-NOT DD1.1 DD1.2.

The frequency of each generator depends on the capacitance of the capacitor and the resistance of the resistor. For a generator on LE AND-NOT DD1.3 DD1.4 - C2, R2 and, accordingly, for a generator on LE AND-NOT DD1.1 DD1.2 - C1, R1. The frequency of the generated pulses is determined by the dependence F=1/T; where T≈2.3CR, subject to the restrictive condition for choosing the resistance of the 240 Ohm resistor

Fig.4.1a


And so let's dwell on the details of the device in Fig. 4.1a. chip K155LA3 or K131LA3, C1 - 2200 uF, C2 - 4.7 uF, C3 - 47 - 100 uF, R1-R2 - 430 Ohm, R3 - 1 kohm, V1 - KT315, V2 - KT361 or other low-power transistors, for example series "MP". 0.25 W dynamic driver with 8-10 ohm voice coil. To increase the power, you can use transistors, for example V1 - GT404, V2 GT402. Power supply 4.5 - 5V

Fig.4.1b


The variant in fig. 4.1b differs from the variant in fig. 4.1a with a more powerful output sound amplifier assembled on three transistors. Details: chip K155LA3 or K131LA3, C1 - 2200 uF, C2 - 4.7 uF, C3 - 47 - 200 uF, R1-R2 - 430 Ohm, R3 - 1 kohm, R4 - 4.7 kohm, R5 - 220 Ohm, V1 - KT361 (MP 26, MP 42, kt 203, etc.), V2 - GT404 (KT815, KT817), V3 - GT402 (KT814, KT816). 0.25 - 0.5 W dynamic driver with 8 - 10 ohm voice coil. Power supply 4.5 - 5V

Rice. 4.2


In the variant in Fig. 4.2, a TV-12 transformer is used as an output amplifier (you can use a transformer from any small-sized transistor receiver). 0.25 W dynamic driver with 8-10 ohm voice coil. Power supply 4.5 - 5V

Option number 4
In the above circuits of intermittent signal generators on the K155LA3 chip, larger capacitors and low resistance resistors are included in the timing circuit, which limits the range of smooth adjustment of the control pulse repetition rate. In repellers, the scheme of which is shown in Fig. 5, a similar drawback is eliminated by turning on the transistor at the inputs of the LE DD1.1, which plays the role of an emitter follower with a large input and low output resistance. Therefore, it is possible to use resistors with a higher resistance than in the previous circuits, and the restrictive condition for choosing a resistance looks like - 240 Ohm Rice. 5

Parts used: chip K155LA3 or K131LA3, C1 - 100 uF, C2 - 4.7 uF, R1 - 260 Ohm, R2 - 430 Ohm, R3 - 1 kohm, Rp -30 kohm, V1 - KT361 (MP 26, MP 42, KT203, etc.), V2 - GT404 (KT815, KT817). 0.5 W dynamic driver with 8-10 ohm voice coil. Power supply 4.5 - 5V.

Option number 5
And one more device on a fairly common foreign chip from the 4000 series. This design is taken from the book "135 AMATEUR RADIO DEVICES ON A ONE CHIP" by Newton S. Braga. (Project 25 Sound signaling device with a powerful output (E, P) page 73)

Although the article refers to the alarm, but this device for repelling underground rodents is great for our topic. The design has a number of positive aspects. Let us consider in detail the principle of operation of the device. The output stage on transistors, they are capable of delivering several hundred milliwatts to the loudspeakers. As in the previous schemes, the device consists of an audio tone generator on the LE DD1.2 and a control oscillator on the LE DD1.1. The signal repetition frequency is adjusted by the variable resistor Rp1, the audio tone - by the variable resistor Rp2. Changing the tone and repetition rate of pulse packets can be done by selecting the appropriate values ​​of capacitors C1 and C2. You can experiment by changing their values ​​according to the purpose of the device. The schematic diagram of the device is shown in fig. 6.

The current consumed by the device is about 50 mA. The supply voltage of the microcircuit is 3-9 V. To improve the acoustic characteristics, the loudspeaker must be placed on a plastic surface or in a small case. Chip CD 4093, domestic analogue of K561TL1.
Rice. 6


Parts used: Rp1 - 1.5 MΩ, Rp2 - 47 kΩ, R1 - 100 kΩ, R2 - 47 kΩ, R3 - 4.7 kΩ, C1 - 47 uF, C2 - 0.1 uF, C3 - 47 uF, C4 - 100 uF. V1 - KT315 (KT815), V2 - KT361 (KT814), speaker 0.25-0.5 W - 4 - 8 ohms. To power the device, square 3336 batteries connected in series are perfect.

I wish you good luck, feel free to experiment, try. The left column offers options on how to manufacture the described devices. And we will move on to the most malicious and causing significant damage - mice, rats, etc.

2. Rats, mice, gophers, kitties, chipmunks

These annoying "neighbors" cause damage not only in the garden, but also in everyday life, in warehouses, in basements, in cellars, food storage places, in the holds of ships, in garages, spoil the wiring of el. food, spread disease, and much more. Think about it - after all, you will spend less money and effort on acquiring or making a scaring device than constantly acquiring poisons, poisoned baits, traps, losing money.

Rodent repellers are used not only in gardens and kitchen gardens, but also in various premises: domestic, warehouse, residential (apartments, offices, country houses, etc.), basements, granaries, as well as industrial and livestock enterprises.

What is the principle of operation of this device? What are its advantages over other methods? The rodent repeller emits ultrasonic waves (with a frequency exceeding 20 kHz), which, in turn, repel rodents.

Ultrasonic frequencies have an extremely negative effect on rats and mice. The emitted sound waves cause them anxiety, fear, so rodents tend to leave the room irradiated with ultrasound. Rat repellers were laboratory tested, as a result of which it was found that with constant exposure, rats and mice experience an increasing stress state, and leave the room within a few weeks. Typically, their departure time ranges from two to four weeks, depending on the type of rodents, their numbers and how strong the ultrasonic radiation is. Mice and rat pups are deaf for two weeks after birth, so ultrasound does not affect them at first. The recommended exposure time is four to six weeks. And as a preventive measure, the device can work constantly.

Let's start with the description of the devices. I want to warn you in advance that at high frequencies we will need a more powerful signal amplification than in devices for scaring away underground rodents, this is due to the peculiarity of the passage of a high-frequency signal in the air and the ability to reproduce the signal by high-frequency dynamic heads. As a result, repellers consume more current, and they should be powered from an alternating voltage network or from a car battery. The average current consumption of repellers at the time of operation is from 250 to 800 mA for an electric meter. Such energy consumption is practically not noticeable, but for batteries it is already significant.

Option number 1
You have already seen the proposed circuit in Fig. 7 in mole devices, the difference is in the output stage. To increase the output power, a composite transistor is used here, and a variable resistor is added to the signal generator. The speaker must be high-frequency with a dynamic head impedance of 8 ohms. Suitable, for example, from a TV - 2GD-36K, 8 Ohm GOST9010-78, or from speakers. To increase stress in our small wards, in addition to changing the length of the pauses with the resistor Rp1, I added a variable resistance Rp2 to change the signal frequency within 15 kHz. This combination increases stress in animals, and the periodic change in the frequency of the sound forces the rats and mice to leave you faster.

The repeller emits a sound signal from 28 kHz to 44 kHz. In the device, the pause-work ratio is 1/3. Supply voltage 5V. The ratio in the choice of resistances is the same as in the devices described for underground rodents on the K155LA3 chip.

Fig.7.

In the circuit diagram in fig. 7, the following parts are used: chip K155LA3 or K131LA3, C1 - 100 uF, C2 - 0.033 uF, R1 - 260 ohms, R2 - 240 ohms, R3 - 1 ohm, Rp1 -30 ohm, Rp2 -220 ohm V1 - KT361 (MP 26 , MP 42, KT203, etc.), V3 - GT404 (KT815, KT817). Power supply 4.5 - 5V.

Option number 2
Although at first glance such a scheme seems complicated, I consider it the most practical and universal. Like all previous options, with proper assembly and serviceability of parts, it starts working immediately. The output power is 0.8 - 1W.

Fig.8.

How to make an emitter for underground rodents.
In different media, a low-frequency sound wave propagates at different speeds and over different distances. As a radiator, we use a regular speaker from an old radio. To increase the efficiency and increase the area of ​​propagation of the sound wave, you can simply attach the speaker to a square or round plastic plate. see fig.

The loudspeaker diffuser, when moving forward, compresses the air in front of it and discharges it from the saddle. These areas of compression and rarefaction go around the diffuser, overlap each other and cancel each other out. When moving the diffuser back, the same picture is obtained. This effect is called an acoustic "short circuit": the diffuser only distills air from one side to the other.

To eliminate this effect, the loudspeaker is mounted on a shield (screen). In this case, the change in pressure in the air layer immediately adjacent to the diffuser will be transmitted and directed further, i.e. more powerful sound emission will occur.

Place the assembled emitter in dense polyethylene so that moisture does not get in and you can bury it in the right place, to a depth of 30-50cm

If you have any questions, you can leave a message at: [email protected] I will gladly share my experience.

The scheme below was collected in his youth, in the classroom of the radio engineering circle. And unsuccessfully. Perhaps the K155LA3 microcircuit is still not suitable for such a metal detector, perhaps the frequency of 465 kHz is not the most suitable for such devices, or perhaps it was necessary to shield the search coil as in the other circuits of the "Metal Detectors" section

In general, the resulting "scribble" reacted not only to metals, but also to the hand and other non-metallic objects. In addition, microcircuits of the 155th series are too uneconomical for portable devices.

Radio 1985 - 2 p. 61. Simple metal detector

Simple metal detector

The metal detector, the diagram of which is shown in the figure, can be assembled in just a few minutes. It consists of two almost identical LC oscillators, made on the elements DD1.1-DD1.4, a detector according to the scheme of doubling the rectified voltage on VD1 diodes. VD2 and high-resistance (2 kOhm) BF1 headphones, the change in the tone of the sound of which indicates the presence of a metal object under the coil-antenna.

The generator, assembled on the elements DD1.1 and DD1.2, is itself excited at the resonance frequency of the series oscillatory circuit L1C1, tuned to a frequency of 465 kHz (the elements of the IF filter of a superheterodyne receiver are used). The frequency of the second generator (DD1.3, DD1.4) is determined by the inductance of the antenna coil 12 (30 turns of PEL 0.4 wire on a mandrel with a diameter of 200 mm) and the capacitance of the variable capacitor C2. which allows you to configure the metal detector to detect objects of a certain mass before searching. The beats resulting from mixing the oscillations of both generators are detected by diodes VD1, VD2. are filtered by capacitor C5 and fed to headphones BF1.

The whole device is assembled on a small printed circuit board, which makes it very compact and easy to handle when powered by a pocket flashlight battery.

Janeczek A Prosty wykrywacz melali. - Radioelektromk, 1984, No. 9 p. 5.

Editorial note. When repeating the metal detector, you can use the K155LA3 chip, any high-frequency germanium diodes and KPE from the Alpinist radio receiver.

The same scheme is considered in more detail in the collection of Adamenko M.V. "Metal detectors" M.2006 (Download). Further article from this book

3.1 A simple metal detector on a K155LA3 chip

Beginning radio amateurs can be recommended to repeat the design of a simple metal detector, the basis for which was a circuit that was repeatedly published in the late 70s of the last century in various domestic and foreign specialized publications. This metal detector, made on just one K155LA3 chip, can be assembled in a few minutes.

circuit diagram

The proposed design is one of the many variants of metal detectors of the BFO (Beat Frequency Oscillator) type, that is, it is a device based on the principle of analyzing the beats of two signals that are close in frequency (Fig. 3.1). At the same time, in this design, the assessment of the change in the beat frequency is carried out by ear.

The device is based on measuring and reference oscillators, an RF oscillation detector, an indication circuit, and a supply voltage stabilizer.

In the design under consideration, two simple LC oscillators are used, made on the IC1 chip. Circuit solutions of these generators are almost identical. In this case, the first oscillator, which is a reference, is assembled on the elements IC1.1 and IC1.2, and the second, measuring or tunable generator, is made on the elements IC1.3 and IC1.4.

The reference oscillator circuit is formed by a 200 pF capacitor C1 and a coil L1. The measurement generator circuit uses a variable capacitor C2 with a maximum capacitance of approximately 300 pF, as well as a search coil L2. In this case, both generators are tuned to an operating frequency of approximately 465 kHz.

Rice. 3.1.
Schematic diagram of a metal detector on a K155LA3 chip

The outputs of the generators through decoupling capacitors C3 and C4 are connected to the RF oscillation detector, made on diodes D1 and D2 according to the rectified voltage doubling circuit. The load of the detector is BF1 headphones, on which the signal of the low-frequency component is extracted. In this case, the capacitor C5 shunts the load at higher frequencies.

When approaching the search coil L2 of the oscillatory circuit of the tunable generator to a metal object, its inductance changes, which causes a change in the operating frequency of this generator. In this case, if there is an object made of ferrous metal (ferromagnet) near the coil L2, its inductance increases, which leads to a decrease in the frequency of the tunable oscillator. The non-ferrous metal reduces the inductance of the L2 coil, and increases the operating frequency of the generator.

The RF signal formed as a result of mixing the signals of the measuring and reference generators after passing through the capacitors C3 and C4 is fed to the detector. In this case, the amplitude of the RF signal changes with the beat frequency.

The low-frequency envelope of the RF signal is isolated by a detector made on diodes D1 and D2. Capacitor C5 provides filtering of the high-frequency component of the signal. Next, the beat signal is sent to the BF1 headphones.

Power is supplied to IC1 from a 9V source B1 through a voltage regulator formed by a zener diode D3, a ballast resistor R3 and a regulating transistor T1.

Details and construction

For the manufacture of the considered metal detector, you can use any prototyping board. Therefore, the used parts are not subject to any restrictions related to overall dimensions. Installation can be both hinged and printed.

When repeating the metal detector, you can use the K155LA3 microcircuit, consisting of four 2I-NOT logic elements, powered by a common DC source. As capacitor C2, you can use a tuning capacitor from a portable radio receiver (for example, from the Alpinist radio receiver). Diodes D1 and D2 can be replaced with any high frequency germanium diodes.

Coil L1 of the reference oscillator circuit should have an inductance of about 500 μH. As such a coil, it is recommended to use, for example, the IF filter coil of a superheterodyne receiver.

Measuring coil L2 contains 30 turns of PEL wire with a diameter of 0.4 mm and is made in the form of a torus with a diameter of 200 mm. This coil is easier to make on a rigid frame, but you can do without it. In this case, any suitable round object, such as a jar, can be used as a temporary frame. The turns of the coil are wound in bulk, after which they are removed from the frame and shielded with an electrostatic screen, which is an open aluminum foil tape wound over a bundle of turns. The gap between the beginning and the end of the tape winding (the gap between the ends of the screen) must be at least 15 mm.

In the manufacture of the L2 coil, it is especially necessary to ensure that the ends of the shielding tape do not close, since in this case a short-circuited coil is formed. In order to increase the mechanical strength, the coil can be impregnated with epoxy glue.

For the source of sound signals, high-impedance headphones with as high a resistance as possible (about 2000 ohms) should be used. Suitable, for example, the well-known telephone TA-4 or TON-2.

As a power source V1, you can use, for example, a Krona battery or two 3336L batteries connected in series.

In a voltage stabilizer, the capacitance of the electrolytic capacitor C6 can be from 20 to 50 microfarads, and the capacitance of C7 can be from 3,300 to 68,000 pF. The voltage at the output of the stabilizer, equal to 5 V, is set by the trimming resistor R4. This voltage will be maintained unchanged even when the batteries are significantly discharged.

It should be noted that the K155LAZ chip is designed to be powered from a 5 V DC source. Therefore, if desired, the voltage stabilizer unit can be excluded from the circuit and one 3336L battery or similar can be used as a power source, which allows you to assemble a compact design. However, the discharge of this battery will very quickly affect the functionality of this metal detector. That is why you need a power supply that provides the formation of a stable voltage of 5 V.

It should be recognized that the author used four large imported imported round batteries connected in series as a power source. In this case, a voltage of 5 V was formed by an integral stabilizer of the 7805 type.

The board with the elements located on it and the power supply are placed in any suitable plastic or wooden case. A variable capacitor C2, a switch S1, as well as connectors for connecting a search coil L2 and headphones BF1 are installed on the housing cover (these connectors and switch S1 are not indicated on the circuit diagram).

Establishment

As with the adjustment of other metal detectors, this device should be adjusted in conditions where metal objects are removed from the L2 search coil at a distance of at least one meter.

First, using a frequency meter or oscilloscope, you need to adjust the operating frequencies of the reference and measuring oscillators. The frequency of the reference oscillator is set to approximately 465 kHz by adjusting the core of the coil L1 and, if necessary, by selecting the capacitance of the capacitor C1. Before adjustment, you will need to disconnect the corresponding terminal of the capacitor C3 from the diodes of the detector and capacitor C4. Next, you need to disconnect the corresponding terminal of the capacitor C4 from the diodes of the detector and from the capacitor C3 and adjust the capacitor C2 to set the frequency of the measuring generator so that its value differs from the frequency of the reference generator by about 1 kHz. After all connections are restored, the metal detector is ready for operation.

Operating procedure

Carrying out search operations with the help of the considered metal detector does not have any features. In practical use of the device, the necessary frequency of the beat signal should be maintained by the variable capacitor C2, which changes when the battery is discharged, the ambient temperature changes, or the deviation of the magnetic properties of the soil.

If the frequency of the signal in the headphones changes during operation, this indicates the presence of a metal object in the area of ​​​​the search coil L2. When approaching some metals, the frequency of the beat signal will increase, and when approaching others, it will decrease. By changing the tone of the beat signal, having a certain experience, one can easily determine what metal, magnetic or non-magnetic, the detected object is made of.

The circuit of a two-tone call on microcircuits is assembled on two microcircuits and one transistor.

Device diagram

Logic elements D1.1-D1.3, resistor R1 and capacitor C1 form a switching generator. When the power is turned on, the capacitor C1 starts charging through the resistor R1.

As the capacitor charges, the voltage on its plate increases, connected to terminals 1, 2 of the logic element DL2. When it reaches 1.2 ... 1.5 V, a logical “1” signal (“4 V”) will appear at the output 6 of the D1.3 element, and a logical “0” signal (“ 0 .4 V).

After that, the capacitor C1 begins to discharge through the resistor R1 and the DLL element. As a result, rectangular voltage pulses will be formed at the output 6 of element D1.3. The same pulses, but shifted in phase by 180 °, will be at terminal 11 of element D1.1, which acts as an inverter.

The duration of the charge and discharge of the capacitor C1, and hence the frequency of the switching generator, depends on the capacitance of the capacitor C1 and the resistance of the resistor R1. With the ratings of these elements indicated on the diagram, the frequency of the switching generator is 0.7 ... 0.8 Hz.

Rice. 1. Schematic diagram of a two-tone call on two K155LA3 microcircuits.

The switching oscillator pulses are fed to the tone generators. One of them is made on the elements D1.4, D2.2, D2.3, the other - on the elements D2.4, D2.3. The frequency of the first generator is 600 Hz (it can be changed by selecting elements C2, R2), the frequency of the second is 1000 Hz (this frequency can be changed by selecting elements C3, R3).

When the switching generator is running, the output of the tone generators (pin 6 of element D2.3) will periodically receive either the signal of one generator or the signal of another. Then these signals are fed to the power amplifier (transistor VI) and converted by head B1 into sound. Resistor R4 is needed to limit the base current of the transistor.

Setting and Details

The trimming resistor R5 can be used to select the desired sound volume.

Fixed resistors - MLT-0.125, trimmer - SPZ-1B, capacitors C1-SZ - K50-6. K155LAZ logic circuits can be replaced with KIZZLAZ, K158LAZ, KT603V transistor - with KT608 with any letter index. The power source is four D-0.1 batteries connected in series, a 3336L battery or a 5 V stabilized rectifier.

Every real radio amateur has a K155LA3 chip. But usually they are considered very outdated and cannot be seriously used, since many amateur radio sites and magazines usually only describe flashing lights and toys. As part of this article, we will try to expand the amateur radio horizons as part of the application of circuits using the K155LA3 chip.

This scheme can be used to charge a mobile phone from the cigarette lighter of the car's on-board network.

Up to 23 volts can be applied to the input of an amateur radio design. Instead of the outdated transistor P213, you can use a more modern analogue of KT814.

Instead of diodes D9, you can use d18, d10. Toggle switches SA1 and SA2 are used to test transistors with forward and reverse conduction.

In order to prevent overheating of the headlights, you can install a time relay that will turn off the brake lights if they are on for more than 40-60 seconds, the time can be changed by selecting a capacitor and resistor. When the pedal is released and then pressed again, the lights turn on again, so driving safety is not affected in any way.

To increase the efficiency of the voltage converter and prevent severe overheating, field-effect transistors with low resistance are used in the output stage of the inverter circuit.

The siren is used to give a powerful and strong sound signal to attract people's attention, and effectively protect your bike left and fastened for a short time.

If you are the owner of a dacha, vineyard or village house, then you know how much damage mice, rats and other rodents can cause, and how costly, ineffective, and sometimes dangerous, rodent control is by standard methods.

Almost all amateur radio homemade products and designs incorporate a stabilized power source. And if your circuit is powered by a supply voltage of 5 volts, then the best option would be to use a three-terminal integral stabilizer 78L05

In addition to the microcircuit, there is a bright LED and several strapping components. After assembly, the device starts working immediately. No adjustment is required other than adjusting the flash duration.

Recall that the capacitor C1 with a nominal value of 470 microfarads is soldered into the circuit strictly in accordance with the polarity.

Using the resistance value of the resistor R1, you can change the duration of the LED flash.