Antipyretic remedies for children are prescribed by a pediatrician. But there are situations of indispensable help for fevers, if the child needs to give faces negligently. Then the fathers take on themselves the resuscitation and stop the antipyretic preparations. What can be given to infants? How can you lower the temperature in older children? What are the most safe faces?
The most simple way to receive a fixed AM signal in the 27 MHz band is possible, as a basis for taking a ready-made gut radio with a radio path on the K174XA2 microcircuit. One of such primers is "Nevsky 402". Reworks are supported by a high-frequency plot of the circuit. I looked at the back of my head, the testimony of the little one 1 (a fragment of the scheme, which is added to the instructions by the virobnik plant).
Then we see everything is necessary for the MW band, a replacement capacitor, a variometer, a magnetic antenna, contour coils, and so on, including elements for adjusting the KB band, switching the bands, and on other tracks that have called, mounting єmo elements indicated by strokes (for example L1") testimonies of the little one 2.
Malyunok 2
The essence of the conversion is clear from the scheme, the input circuit is simple (under-construction capacitors are not needed, the fragments obtained in different areas of the range are not needed), the foldable heterodyne circuit, which is to be changed, is replaced by a quartz resonator and a reference circuit on L2. As a result of accurate matching of the input and heterodyne circuits on one point to the range (frequency to the channel that is received), the sensitivity of this point is significantly increased.
The new coils L1" and L2" are wound on the frames in the old coils of KB range, they are the same and can be 8 turns of the thread PEV 0.2.
The tuning is done in the traditional way, the L2 "tuning is driven by the stable operation of the local oscillator, and the L1" tuning is the maximum sensitivity (more precisely, the tuning of the input circuit).
With the frequency of the resonator, shown in the diagram, the reception of the working channel is 26945 kHz, recognized as a security alarm.
The receiver was tested in combination with a radio microphone with amplitude modulation and in combination with a radio control system with a frequency subdivision of the channels, in another case, a low-frequency signal to the system of the simplest contour decoders was fed directly from the telephone jack.
It is possible to convert the receiver to a small-sized radio station, by adding it, we will forgive AM by transmitting and switching the "reception-transmission" mode (to switch the antenna and live). A diagram of such a transmission is shown in figure 3.
The coil L1 is wound on such a frame as a contour coil of the HF KB range of the receiver, so that it can cover 8 turns of PEV 0.2, L2 can have the same frame, but also cover 12 turns of the same thread. Throttle DL1 - winding on a resistor MLT 0.5 100 to whom, revenge 60 turns PEV 0.12. Throttle DL2 - on a ferite ring K7X4X3 - 120 turns PEV 0.12.
Scheme of a light self-contained transistor priymach to work on a complex of radio control equipment. Frequency range 27 MHz.
Schematic diagram
Substroyuvalny resistor R2 ensures the installation of a working point when the receiver is set. The intermediate resistor R1 shifts the output of the fret of the transistor VT1 when the engine R2 is installed in the process of adjusting the extreme upper position.
From the output of the R5C7 low-pass filter for detecting, the signal should go to the input of the ULF, selected on transistors VT2 and VT3. Bessreddnє switching transistors with circuit cooling with a deep negative link on the constant stream through the resistor R7 ensures good thermal stabilization of the position of the working point.
Rice. 1. Schematic diagram of a self-contained transistorized receiver-supergenerator for radio control at 27 MHz.
The high coefficient of ULF strength in such a scheme can reach 1000-3000. Em_terny repeater on transistors VT4 ensures the decoupling of the receiver from the advancing cascades.
Details and design
Drukovana payment is shown a little 2 and daily comments for more. All capacitors, krіm elektrolitichnyh C8 and C10, are due to ceramics.
Rice. 2. A board for a self-contained receiver of radio control with several transistors was designed.
Substroyuvalny resistor R2 can be either SPE-386 or RSh-bZMg. Usі transistors - either KT315, or KT3102 with any letter indexes. Contour coil maє 7 turns in a dart with a diameter of 0.5 mm on a frame with a core made of a carbonyl core.
The frame diameter can be in the range of 5-9 mm. Throttle L1 - standard at 20-68 μH. Like an antenna, the line is victorious, or a flexible wire with a length of 20-40 cm.
Nalashtuvannya
The adjustment of the field in the setting of the optimal mode of overregeneration for the help of R2 and the adjustment of the L2C5 circuit in resonance with the signal of its transmission. Capacitor Sat is responsible for mother Pochatkov's capacitance of 15 pF. This value is specified in the process of adjusting to the maximum amount of voltage, which is monitored by the oscilloscope at the point of connection of capacitors C7 and C9.
The adjustment of the ULF is brought up to the installation of a voltage, equal to 4, on the emitter of the transistor VT4, with a way to select the support of the resistor R7, for which it is timely to replace the change.
Z'ednuvalni droti due to buti yakomoga short, so that you can aim at the VT2 base. For the frequency of the oscilloscope before the output of the receiver, you can turn on high-ohm headphones (for example, TON-2) and adjust the position of the R2 motor and the value of C6 according to the maximum noise density, which can be heard when the transmission is switched off.
Let's increase the transmitter (may be on the way, which works in the mode of amplitude modulation with signals from the output of the encoder) and adjust the input circuit to the maximum loudness. Other options for choosing the position of the motor of the potentiometer R2.
Dnischenko V. A. Remote control by models (500 schemes for radioamators).
The receiver of the radio station is based on the import of the MC3362 microcircuit. The peculiarities of this microcircuit are the frequency change, the first heterodyne oscillator is energized. Analogue of MS3362-AK9401 descriptions in .
The basic electrical circuit of the 27 MHz receiver is shown in Fig. 1. The signal received by the antenna through the "reception-transmission" jumper should be sent to the URCH, selected on the field-effect transistor VT1 type KP327. Zastosuvannya of this transistor is wised up, so that it is possible to vindicate the integration of diodes, that protect it from breakdown. Tse to bring up to the rise of arrogance, like in the case of a soldier, so in the case of a robot, priymacha near the working gears.
The signal strength from the URF through the coil 15 is sent to the input 1 of the MS3362. After the input signal is mixed with the GPA signal on the output 19, a signal of the first intermediate frequency of 10.7 MHz is seen, which through the Z2 piezofilter goes to the input of another switcher. To remove another intermediate frequency of 465 kHz, quartz ZQ1 is switched to a frequency of 10.24 MHz, connections to pin 4. The inductance L6 ensures that the frequency of the quartz changes in small intervals, which allows you to accurately drive another local oscillator. On view 2, you can control the frequency of the local oscillator. Resistor R5 є navantazhennyam.
As a result of the transformation, another IF signal is seen on view 5, which, through the p'ezofilter Z1 (465 kHz), enters the input of the subsidiary-intermediate decoupling from the main stronger signal (visnovok 7). After detecting the audio frequency signal, through 13 low-frequency filters R12R14 C21C22, go to the loudness control R15. Resistor R8 is vicorated to adjust the threshold for switching on the noise suppressor. For indication I will become a scheme for suppressing noise with a VD1 light diode.
With the appearance of a core signal (carrying) the light is switched off, the transistor VT2 closes and the signal goes to the ULF input. ULF positions from . Moreover, there is no need to beat the hard transistors, like. Quite enough transistors KT502, KT503 or KT3107, KTZ102. As it is assigned to, to bring in the creation of the "gathering" type, the stench is weakly added to the discourse of the language. Set the strum of the pilot without a signal to 0.5.0.6 mA.
You can also select an audio frequency switch for the circuit shown in Fig.2. Set the strum to 5.6 mA in which direction without a signal. In other respects, the parameters of the power supply are the same: the damping of the strum for a maximum intensity of 25.30 mA, the output power is up to 150 mW. Resistor R25 (Fig. 2) restores half the voltage of life on the emitters VT7, VT8, and with the help of R29, sensitivity is necessary.
Nashtuvannya. Since the introduction of 5 microcircuits in the form of a p'ezofiltra, to the new type of the GSS, a SN signal with an amplitude of 200.300 mV and a frequency of 465 kHz is supplied, modulated by a harmonic signal of 1 kHz. The coil L8 is adjusted to the maximum output voltage on the resistor R15. The noise reduction scheme is due to buti vimknen (rux R8 is located at the top of the position scheme). P'ezofiltr bazhano vikoristovuvaty eight-crystal, as the remaining on the view of chotyric-crystal can be more steeply fall off the frequency response. Bad results come out when replacing the L8 coil with a p'zoceramic resonator at a frequency of 465 kHz. Resistor R11 sets the output voltage R15 between 15 ... 20 mV. Opir resistor R11 to become 3.10 kOhm. After soldering the wire 5 on the plate, the wire 19 is soldered and a frequency-modulation signal of 10.7 MHz with an amplitude of 300.400 μV is applied to the input of the p'ezofiltra Z2. By changing the inductance of L6, adjust the frequency of another local oscillator by minimizing the sinusoidal signal, which is taken from R15.
Up to 21 and 22 connections to the GPA circuit L7C19. From the viewpoint 20, a signal with a GPA frequency with an amplitude of 200 ... 300 mV is fed to the input of the synthesizer frequency dial (control point 2). On visnovok 23 there should be a strong voltage from the output of the frequency-phase detector of the synthesizer (v.4). Having applied a signal with a frequency of 27.2 MHz and an amplitude of 10 ... 15 mV from the GSS SN, wrap the L8 core, the PLL system of the synthesizer does not work. Switching the channels of the frequency synthesizer, control the voltage on the output 23, but not less than 1 V.
By changing the input voltage to 2 ... 3 μV, in the middle of the range, adjust the coils L3, L4 for the maximum voltage on the ULF. In the rest of the week, choose R9 according to the minimum hysteresis of the inclusion-switching of the noise reduction system.
The microcircuit can be switched with the same local oscillator, supplying a signal with an amplitude of 200 ... 400 mV to the windings 21 or 22.
For an hour of experimentation, the MS3362 chip showed performance up to 500 MHz. As the first local oscillator vikoristovuvavsya generator GC-158, and the input signal was fed from GC-168 to the capacitor SP. Pіd'єdnavshi to the joint venture shmatok drot like an antenna, and rebudovayuchi generator, which vikoristovuєtsya like a local oscillator, in the range of 400 ... 450 MHz, you can listen to the radio station trunking and style communication.
The scheme of the doctored payment of the receiver with ULF fig. 2 is shown in fig. 3 and fig. 4. The L8C20 circuit is replaced by a piezoresonator at 465 kHz, with its resistor R11 set to 3.10 kOhm. Capacitors C4, C9, C13, C16, C17 are unpackaged, they can be soldered conductors. Resistor R5 and capacitor C22 are not installed on the other board. Loop capacitors are placed without a middle on the frame of the circuit and closed by a screen. On another plate, the foil on the side of the parts is stripped like a screen and is closed with the case.
Coil parameters: L1-20 turns; L3, L4-12 turns; L2, L5 - 4-6 turns; L7-30 windings of the thread PEV 0.25; L6 -55 turns of the thread PEV 0.15; L8 - 250 turns of the thread PEV 0.1.
Literature:
1. Alexandrov I. Vuzkosmugovy ES primer AK9401 for radio station // Radioamator. -1995. - No. 1-S.46-47.
2. Bilousov O. Economic UZL// Radioamator. -1997. - No. 6.-S.19.
3. Vasiliev U. Modern car radio station 27 MHz // Radio amateur.-1997.-№3,-p.36-38.
4. Opanasenko Z. Frequency synthesizer 27 MHz // Radiumator.-1998, - No. 7.-S.55-56.
Tsej nabіr allow to pick up the dream of faceless lads (and maybe girls) - a portable radio station, a walkie-talkie. It’s not uncomfortably folded and may be zowsim awkwardly laid out - and you have a radio station in your gut, which can be creased - at the city and the field, at the forest in the dacha. Highly visible tightness of the transmission is a pledge for a decent distance of the link. A civil band 27 MHz do not require any valid documents. An RF probe for setting up the station is included in the kit, you only need a multimeter! No frequencies and oscillographs!
Characteristics:
• Working frequency: 27 MHz;
• Exhaust pressure: 50 mW;
• Modulation: frequency (FM);
• Sensitivity of the receiver: 3...5 µV;
• Spozhivanie strum in mode movchannya: 15 mA;
• Nominal voltage of life: 9 V (1 battery type "Krona");
• Folding: 3 balls;
• Pick up time: Close to 5 o'clock;
• Sizes of the handmade board: 111 x 64 x 2 mm; 106 x 54 x 2 mm;
• Packing: OEM;
• OEM packaging sizes: ~255 x 123 x 35 mm;
• Outbuildings: ~111 x 64 x 25 mm / ~106 x 54 x 20 mm;
• Zagalna masa set: ~400 g.
Contents of delivery:
• The fee is free;
• Set of radio components;
BONUS! A coil of tubular solder POS-61 (~ 0.5 m);
• Scheme of pinout of components;
• Scheme of color marking of resistors;
• Instructions for choosing and operating.
To enlarge, click on the picture
(Navigation behind pictures is done with arrows on the keyboard)
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If the intermediate frequency in this receiver is chosen to be noticeably low (400-600 kHz), then the circuit for operation at such a frequency can be made stable without going into any special steps to stabilize it. At that hour, as the reach of great stability, the adjustment of the LC circuit at frequencies close to 30 MHz (27 MHz) is easy, a strong infusion is applied and equal capacities, and temperature changes in the geometric dimensions of the coil frame, core.
Ale є i “spoon of dog” - smoothly build the IF tract with high selectivity along the suture channel. The experimental scheme of the primal tract, inspired by the improved principle, is shown as a small picture.
The signaling path on the MC3361R microcircuit, which replaces the radio receiving path of the VUZ link behind the superheterodyne circuit with one-time frequency conversions. The input circuit C3-C4-L1 has been adjusted to a frequency in the middle of the range 27.055 MHz - 27.255 MHz.
The local oscillator circuit is typical for the Q1 quartz resonator. At the output, switching on the switching frequency, the IF circuit L2-C11-C12-C13.1, which is behind the auxiliary section of the replacement capacitor C13, can be switched between 400-600 kHz. This scheme has a single FPL circuit, which, obviously, is short. From the coil, link L3, the voltage of the inverter is connected to the UPC and the frequency detector of the microcircuit A1.
The frequency detector uses another IF circuit - L4-C15-C14-C13.2, it will be switched over at the same time with the L2-C11-C12-C13.1 circuit. The voltage of the ZCh is taken from the output 9 A1. In this circuit, the MC3361R microcircuit is included behind the simplified circuit, - without the front URCH, that noise reduction system.
The antennae of the coils are wound on the frames in the contours of the submodules of the radio channel (SMRK) of the 3-USCT televisions. Coil L1 to take 12 turns with the introduction of the 3rd, darts PEV 0.31. Coils L2 and L4 are the same, - 50 turns each of PEV 0.12. Coil L3 - 10 turns PEV 0.12, won wound around coil 12.
Only yoga sections for AM bands are victorious.
The primary path of the letters of choice for experimental purposes, therefore, the construction was not capitalized. Installation of chimes in a mock-up way near the case on the dismantling of the other board of the TV module for the radio channel SMRK-1-6 (the board is turned over by the tracks in the middle). The replacement condenser of rotting at the central part of the trussed plate, in front, on the place of the second installation, removed the trussed tracks and drilled one for the th shaft, and open two for the crepe screws.
The primary path, not marveling at the simplicity of the circuit, showing a good robot to do it, although on the high-frequency edge of the range it was suspected that there was a breakdown in the IF circuit and the detector one. Ways to the fullest, - the introduction of the URF, the use of a 2-3-lank FPF and the yoga for additional varicaps (KVS-120, for example), the introduction of a typical noise reduction system and the indicator of adjustment.
