Keywords: tube radio circuit
Japan: 1965 Total number: Section 5 (Total No. 113) Page 2: Page 16 Bar Ed: Electronic Management Knowledge Topics: Simple Electronic Tube Radio Record Elepers: Zhou Zhao Early Simple Electronic Tube Remodel The electrical resistance and capacitors applied, except for a few, and most of the values do not require very accurate. Many resistors and capacitors are based on experiments, or to design what equipment they have. Moreover, the component product itself has an error, or even the error is larger than 20%. However, the enthusiasts of beginners don't understand this. When they simulate the lines designed by others, they are not good at using their existing values approximation, but they can purchase the same number and the same part of others. This is unnecessary, and it is not necessary to get the best results. This paper provides some introduction of various resistors and capacitors commonly used by simple electronic tube radios, and numerical allowances, and the principles of varieties, for all introductions for your reference. The drawings are a comprehensive line diagram of a DC three lamp regeneration radio. The so-called synthesis is to integrate various common circuits together. But actually not every radio has so many levels and parts. The enthusiasts can choose from the lines that are designed or selected, and choose.
Be
Capacitor selection C1 - antenna delivery capacitor
Because it is a high-frequency pathway, the capacitors of mica media or ceramic media should be used, and the quality of non-leakage paper dielectric capacitors can also be used; but because of its value needs to be determined according to the antenna, it is often used for fine-tuning ceramic capacitors. The common value is 25 ~ 1000 piconal (PF). The value of this capacitor can improve the selectivity of the radio, and the value can improve the sensitivity. If the antenna is used, the antenna is used short. C2 - Tuning variable capacitor, or a single variable capacitor
Most of our commodities are 360 pic minus (that is, 0.00036 microclice); there is also a kind of 495 microscopic law. The latter covers the band wide, but the volume is much larger; a new product in recent years is 460 pic mini. The pocket radio requires a small size, optional solid media; but the performance of the air medium is better. C3 - Check-level gateway detection capacitor
It is also a high-frequency pathway. Its quality and unity directly affect the performance of the radio. Therefore, it is necessary to use high quality capacitors such as mica media or ceramic media; paper media is barely available, but do not leak electric. When receiving the medium wave broadcast station, the common value is 250 pic minus, but between 100 ~ 300 picogenesis, the performance change of the radio is not significant. C4 - Regenerated series capacitor
Its function is to prevent regenerative variable capacitors from moving high-pressure short circuits. The common value is 0.01 microfales (μF), the paper can be used, requiring capacitance to not strict, some are small, but minimum should not be less than 100 microscopy. C5 - regenerated variable capacitor, sold common value of 100 microscopic law
Alternatively, it is also possible to use 360 piconal variable capacitors, but at this time, C4 should be used in a small point, and use 200 to 500 microscopy. This can reduce the effective capacitance of all C5 to be screwed to make the control easily. C6 - Check-grade curtain bippass capacitor
It is often used in 0.05 microfaper to fix the capacitor, and the machine can work normally at 0.01 to 0.5 microscopic range, but it is better to choose a larger in the possible range. C7 - check-level screen loaded bypass capacitor
It is not required to be high, the paper die is, and the capacitance value can be selected within the 100 to 1000 piconal scope. This capacitor is only controlled in the regenerative coil in parallel with a potentiometer, and there is a low level, the value is strong, and the value is small. C8 - Coupled capacitors at all levels, or delivery capacitors
There are several such capacitors in the figure, and the principles are the same. Commonly used 0.01 microfained paper capacitors, as long as they do not leak electric. The capacity is selected from 0.006 to 0.1 microscopy. The pocket radio can be smaller, the volume can be small. Its capacitance hours will be slightly small, especially for bass weakening, but if you use headphones, it doesn't matter if you have a problem. If the next level of the gate leakage resistance is used, then C8 cannot be used too much. C9 - voltage amplification level curtain bippass capacitor. The principle is the same as C6. C10 - voltage amplification of the right bypass capacitor. The capacity range is often 100 ~ 1000 pico-microscopic; paper dielectric. C11 - Tone Capacitor
It takes part of the high-stroke side of the power amplifying the power to the speaker, so that the sound is not too harsh, which is more round. Commonly used 0.002 microcarbon-free capacitors, it can be selected between 0.001 to 0.006 microscopic, and it is also useful to 0.1 microfaway. The amount of capacity is large, but it is too big, and the sound is too dull and not listening. C12 - filter capacitor
Often use 8 ~ 30 microfained electrolyte capacitors. Its role is when the battery is old, preventing a screaming, such as a long-term, whispering. When the resistance is selected for the selection resistor, if the conditional license uses some carbon-membrane resistors, this resistance is better, the size is small, the resistance is accurate, the work is stable, and the murmur is small. But another carbon rod resistance (or a carbonaceous resistance or synthetic resistance) is cheaper, which is often used for the majority of enthusiasts. The current of the DC radio is smaller, so the resistance has little power, except that the power of R10 is large, and the general use of 1/4 to 1/2 watts is sufficient. R1 - Check-level grid leakage resistance
It is often used in 2 megoes, and can be varied between 1 to 5 megah (μΩ). There are a few lines to use 10 megohms. This resistance value is often determined by the ethical supply voltage used by the radio. The high voltage is small. This will be stable in this way; if the voltage is low, so sensitivity will increase. It is generally replaced according to the listening effect when the machine is listened. R2 - Adjusting the potentiometer for regeneration
It is best to use 10,000 o'clock (κΩ), and the adjustment is more meticulous, and it can be used to use 50 kΩ, but the adjustment is thick. If you use more than 100 kilometers or more, it is necessary to use the method of connecting the resistance in parallel to improve, otherwise it is difficult to adjust. R3 - Reprimatorial curtain bump resistance
When R4 is about 250 kΩ, R3 often uses 1 megohms to 2 megah; when R4 uses 50 kilometers or with inductive coil, it is often used to use 20,000 to 50,000 Euro. The size of this resistor will affect the strength of the regeneration, the use is small, the codage voltage is increased, and the tube gain is improved, and the regeneration is stronger. Some circuits use a potentiometer instead of this resistance to control regeneration, and its effect is good. Commonly used 50,000 Euro, 100 kilohthalm (or 500 kΩ), which is planted according to the size of the original curtain resistance. For safety, it is best to connect one 30,000 or 100 kΩ in series between B + to this potentiometer. R4 - Retriever-grade screen load resistance
Its resistance is fixed according to the electric supply voltage. When e-e-is used in 45 ~ 67.5, the common value is 100,000 or 300 thousand. When B + is used in 15 to 22.5, the common value is 20,000 or 50,000. Originally used, the output sound is large. However, if the ethical voltage is not high, it may be insufficient after it is too large; it will regenerate it, but the output audio voltage is smaller. The principle of selecting is to ensure that the regeneration is sufficient, and it can be determined when the test machine is required. R5 - Volume Control Potentiometer
It is often used in 500,000 Euro, 470 kilometers and 560 kilo, also uses 1 megohm. R6 - voltage amplification level gate leakage resistance
The common value is 500 thousand to 1 megohm. Some machines use large gate leaks, R6 is to be large to 5 megah to 10 megohms. With a small, the output volume will be small, generally better, but consider the tube type, and to consider the capacitor and the C8 is used, the C8 should be small. R7 - voltage amplification of the grade curtain resistance. The common value is 1 to 2 megohms. R8 - voltage amplification level screen load resistance
The common value is 100 ~ 300 thousand. Its value is also determined according to the high low of the electric supply voltage. However, this level does not have a weak problem, so it is generally used to be larger than the detection. R9 - Grid resistance of power amplification level
The common value is 500 thousand to 2 megohms. When R9 is used, C8 should be small. R10 - Power enlargement Raster negative voltage resistance
Its value affects the magnification performance and signal fidelity of the power unit. Because this gate negative pressure is formed by using the DC current flowing through the Bible. In order to maintain a certain bias, R10 will depend on the tube used by the radio. When only 1 to 2 tubes, R10 usually uses 700 to 800 o'clock; when there are 3 to 4 tubes, use 400 to 500 Europe; when there are 5 ~ 6 pins of 200 to 400 Europe. This resistance has the effect of protecting the tube filament. If it is a low e-electric radio, it is unnecessary to have this resistance. (Zhou Zhao early)
Our other product:
