Author: Petrosani Children's Club
Quarterly magazine of the circle of electronic constructions and amateur radio
Coordinator: Prof. Kovacs Imre - YO2LTF
The structure of the magazine
I. Program of the electronics contest - 2007 Edition - Pitesti
1. Fundamental notions about electric current, electric quantities, passive circuit elements
2. Active circuit elements
2.1. Semiconductor diodes
2.2. Bipolar transistors
2.3. Unipolar transistors (TEC-J, TEC-MOS)
2.4. Thyristors. triacs
2.5. Optoelectronic devices
3. Electronic circuits
4.2. Tilting circuits
5. Digital electronics
5.1. Elements of logical algebra
5.2. Integrated logic ports
6. Electrical and electronic measurements
6.1. The measurement process
6.2. Classification and structure of electrical measuring devices
6.3. Analog measuring devices
6.5. Direct current electrical measurements
6.6. Electrical measurements in single-phase alternating current
II. Let's interpret unconventional units of measurement correctly
The decibel is a unit of measurement for the ratio between two quantities = relative value. If it is the ratio of two powers, the mathematical value of the ratio expressed in decibels is: [dB] = 10xlog (P2 / P1), and if it is about voltages or currents: [dB] = 20xlog (U2 / U1) or [dB] = 20xlog (I2 / I1);
This unit of measurement appeared when it was found that the human ear has a logarithmic perception of sound intensity. The human ear perceives the doubling of the sound intensity when the power of the signal source increases four times…
III. Stereo Amplifiers with TDA 2003
This assembly was made at the inter-county competition - Constanta 2007. Stereo amplifier TDA 2003 is a mounting intended for stationary or car audio-radio-TV equipment, where a maximum power 10 W it is considered sufficient.
In order to be able to function properly, this assembly will be supplied with a very well filtered and possibly stabilized voltage, in the field +12 V… +18 V, absorbing a current of 2.5… 3 A at maximum power. The assembly can be used in a device in which a final floor is required, or with a dedicated housing…
IV. Mounting with tricolor LEDs
The assembly was practically made by the children from the electronics circle from the Children's Palace from Botosani. The main part is the type integrated circuit CMOS - CD 4060, which is an asynchronous binary counter, which contains an oscillator in the capsule.
The maximum division that can be obtained is 16384 depending on the "Q" outputs. The supply voltage is between 6-15 V, the working frequency is maximum 5 MHz, the maximum output current is 15 mA.
V. Serial cables
About the construction of the cable used on Nokia 3210 (complete diagram); the integrated circuit is used MAX232.
VI. Digital photography for beginners (tips, tutorials, ideas)
How to make people look good in photos:
Light: we usually don't think too much about lighting when we have to photograph a subject that is in a hurry or doesn't cooperate with the photographer. The light used, however, helps the most to render a good quality image. If the subject is outdoors, we all know the saying: "with the sun behind". But that doesn't help much on the subject, which will definitely close your eyes due to the too strong direct light.
The solution is to ask the subject not to look directly at the Sun, and to compensate for the shadows that appeared on the face with a flash. Inside, place the subject close to the window and use diffused light from outside. A film of great sensitivity, 400ISO / ASA, will help reduce contrast and achieve a sufficiently short exposure time for clear exposure.
Shooting angle: choose an angle that favors the subject. The camera must be at eye level, but if we want to "hide" some imperfections, we can change the angle. Frame the subject as much as possible: removing non-essential elements from the image, helps to emphasize the subject. Come close to the subject, frame from the middle up, use a telephoto lens or zoom telephoto…
ARE YOU COMING. Curiosity
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