|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Use of old parts in voltage multipliers. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Radio amateur designer Currently, many popular amateur radio devices contain a voltage multiplier that converts the voltage of the 220 V electrical network into a high voltage of 2000 ... 4000 V. These can be devices designed to fight cockroaches, devices for air ionization. Schemes of such devices have been repeatedly published in amateur radio literature, for example, in [1, 2]. In the devices from [1, 2], for the manufacture of a high-voltage multiplier, which is the main part of these designs, modern small-sized parts are used, so the dimensions of these devices are insignificant. However, it should be noted that almost all small-sized high-voltage parts that are part of a high-voltage multiplier are quite expensive. Often there is no need to manufacture a small version of these devices. In this case, for the manufacture of a voltage multiplier, you can use old radio components that have a high operating voltage - 600, 1000, 2000 V, but also large dimensions. These can be old capacitors of the MBG type, old high-voltage diode poles of the D1004D1010 type and similar radio components of the last century, which are now not used in modern technology and are sold at radio markets at low prices. The cost of devices made using old radio components will also be low. In simple high voltage multipliers, the initial voltage for subsequent multiplication is taken directly from the 220 V electrical network. However, in the case of using high-voltage parts to build voltage multipliers, it is advisable to use the initial multiplication voltage not from the household electrical network, but increased several times, as much as they can withstand the high voltage parts used. Using an increased input voltage at the input of the multiplier will reduce the number of multiplication stages and thereby reduce the number of parts used to build a voltage multiplier. The easiest way to initially "multiply" the mains voltage is by using the resonant method, as shown in Fig.1.
As can be seen from this figure, the resonant voltage multiplier is a series circuit that has resonance in the 50 Hz frequency region. Therefore, on the elements of this circuit, on the coil or capacitor, there will be an increased voltage. It will be the higher the resonance of the circuit will be closer to the frequency of 50 Hz, which is used in the electrical network. However, it is necessary to avoid the equality of the resonance frequencies of the network and the circuit, since in this case there will be an extremely high voltage on the circuit elements L1 and C1, which can lead to the failure of these elements. As the inductor L1, use the filter choke of a tube TV or receiver. Filter chokes are now practically not used anywhere, and their cost in the markets is low. It is quite possible to use as L1 the primary winding of a small-sized network transformer or the anode winding of an old "sound" transformer from a tube receiver or TV, or the primary winding of TVK. The capacitance of the capacitor C1 depends on the value of the inductance L1 and the desired initial voltage at the input of the voltage multiplier. It is advisable to select the capacitance of the capacitor experimentally, starting with small values, for example, from 0,1 μF. The resonant frequency of the circuit must be set above the mains frequency of 50 Hz. This will have a favorable effect on the operating conditions of the coil L1. For most filter chokes used in old equipment to obtain a resonant voltage in the range of 600 ... 1000 V, the capacitance of the capacitor C1 can be in the range of 0,25 ... 2 μF. Capacitor C1 should have as high a working voltage as possible, in any case it should not be less than the voltage existing on the capacitor during resonance. The highest voltage will be on one of the elements of the circuit shown in Fig. 1, and on the element that has a higher resistance to alternating current of 50 Hz. In our case, when the resonant frequency of the circuit is higher than the mains frequency, this will be a capacitor. There will be a higher voltage on the capacitor than on the inductor, this is an important condition for the reliable and long-term operation of this element. As already noted, it is quite possible to obtain a voltage across the capacitor C1 in the range of 600 ... 1000 V. This will allow the circuit from [1] to use not a quadrupler, but a voltage doubler. A simple voltage doubler is shown in Figure 2.
In the circuit from [2], instead of multiplying the mains voltage by 8, you can use tripling the voltage that exists on the capacitor C1 (see Fig. 1). A simple voltage tripler is shown in Figure 3.
In some cases, it is advisable to use a voltage quadrupling circuit, which is shown in Fig. 4.
Naturally, when designing such multipliers, one should not forget that they must be connected to a high voltage source through current-limiting resistors with a resistance of at least 1 MΩ. This condition must be observed for the safety of working with high-voltage voltage sources. But not always multiplying the mains voltage by the elements of the resonant circuit is the best solution. Sometimes the situation is different. At the disposal of a radio amateur there are many diodes and capacitors that have a relatively low operating voltage of 200 ... 300 V. In this case, the voltage multiplier assembled using them cannot be directly connected to a 220 V electrical network. the peak at the same time will reach 220 V! And this will already lead to the failure of the radio components used in this voltage multiplier! In this case, it is rational to use another option: reduce the voltage at the input of the multiplier, but at the same time increase the number of multiplying chains. The voltage at the input of the multiplier can be reduced by connecting this voltage multiplier to the electrical network through a capacitor voltage divider, as shown in Fig. 5. In this case, the ratio of capacitances, therefore, and their reactance will determine the output voltage at the output of the divider.
Of course, with an increase in the number of multiplying chains, the dimensions of the device will increase. But this can be justified by the cheapness of the components used. When building voltage multipliers, it should be remembered that it is not recommended to connect diodes and capacitors in series to increase their operating voltage, since the reliability of such a chain will be low. It is more reliable for the voltage multiplier design to follow the path of increasing the multiplication stages. References:
Author: I. Grigorov
The world's tallest astronomical observatory opened
04.05.2024 Controlling objects using air currents
04.05.2024 Purebred dogs get sick no more often than purebred dogs
03.05.2024
▪ Phosphate fertilizers will last only 10 years ▪ Pomera DM30 digital typewriter with E Ink screen ▪ What do poisonous mushrooms smell like? ▪ Display controller ELSA Datapath FX4 ▪ Contact lenses that project information into the eyes
▪ section of the site The most important scientific discoveries. Article selection ▪ article The Whore of Babylon. Popular expression ▪ article How did Mark Chapman manage to play the role of John Lennon? Detailed answer ▪ article Charger for rural workshop. Encyclopedia of radio electronics and electrical engineering
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page