As you know, the greater the number of elements in the design, so it is less reliable. To increase the reliability of electronic devices and selection circuitry. This will be the conversation below.
Permissible variation of AC voltage in household electrical network In the 220 — ±5 %. A more significant increase in voltage may result in damage to consumers of electric energy. In the cities, compared to villages, mains is more stable, which is ensured by the presence of numerous compensation substations, powerful transformers which equalize” voltage with changes in energy consumption However, in spite of it. in the evening and night hours, especially in summer (when not in use electric heating devices) due to the natural reduction in electricity consumption (all asleep), the voltage could rise to 245 — 250 V.
Electronic control units of tension are not new in modern developments. The proposed device differs from the majority of them use as the base timer КР1006ВИ1 and unusual sound effect that is activated if the power of controlled DC voltage, thanks to the use of flashing LEDs L36- piezoelectric capsule with a built-in generator emits a sound similar to the siren of the fire truck.
Electronic devices and components, in the terminal stages which employ electromagnetic relays, to this day has not lost its relevance among radio Amateurs. Despite competition from thyristors and optoelectronic devices, circuits control the load devices remain niche where the solenoid is indispensable. Their popularity among radio Amateurs due to the low cost, versatility (multiple groups of contacts), high reliability, compactness of the housing. Therefore, the use of low-power relay becomes the optimal solution when switching electronic components medium to high power high-voltage electric circuits (in the limited dimensions of the devices).
It can be used for protection of vehicles, equipment of various premises. The “key” to the lock is a combination that is dialed using the three buttons. Easy change of code, the possibility of using two-digit combination that is easy to remember, low voltage power and small size are the main advantages of the proposed design.
Among the many electronic devices a special place is occupied by a simple acoustic alarms, sensors which thanks to its versatility can be used in the home is almost unlimited: from security systems to automated switches or as parts of more complex devices activated by noise (acoustic) impact. For example, warning of high levels of noise in the room (now such devices is becoming more important). As a special case, acoustic sensors can be used even in the foci, for example, on a Christmas tree, when the words “Christmas Tree!” will automatically turn on the light garlands.
To radio sounded good on the UHF band, it should be adjusted to exactly take the radio. Will help you with this indicator fine adjustment circuit of which offers Bulgarian journal “Radio Television Electronics”.
That fuse in the radio, will alert you to the simple automatic device, scheme of which was published the magazine “Radio Fernsehen Elektronik” (Germany). While a fuse F1 (see figure), the voltage between the emitter and base of transistor V1 is equal to zero and a semiconductor device is closed. Once the fuse will burn immediately on the basis of V1, a voltage is applied, opening the transistor and the led B1, included in the collector circuit will light, indicating an “accident”.
The creation of remote electronic devices control various actuators were promising direction in the radio even during my “pioneer” childhood in the 1980-ies. Then, under the guidance of mentors, we enthusiastically gathered such equipment using discrete components. She usually had a range of 5 — 6 m and it barely fits in the box size 300х300х150 mm. If it was possible to assemble at least a fortnight instrument remote control model boats or aircraft with a transmission range of teams at 20 — 30 m, it was considered from us (10 to 12-year-olds) with great success.
Motorists made electronic blocks of ignition, as a rule, according to the classical scheme consisting of a high voltage source, a storage capacitor and a thyristor key. However, such devices have several drawbacks. The first of them is low efficiency. Since the charge storage capacity can be likened to the charging of the capacitor through a resistor, the efficiency of the charging circuit does not exceed 50%. So, about half consumed by the power Converter will be allocated in the form of heat” on the transistors. So they need more heat sinks.