Circuit-Zone.com - Electronic Projects
Posted on Saturday, May 22, 2010 • Category: FM Transmitters
This FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor BF200 (T2), a driver built around transistor 2N2219 (T3) and a power amplifier built around transistor 2N3866 (T4). A condenser microphone is connected at the input of the oscillator.
Posted on Thursday, May 20, 2010 • Category: Miscellaneous
This electronic speed control (ESC) for brushed motors combines the features of two of my earlier designs. One was a high-rate 30A ESC with a brake, and the other a high-rate 12A ESC with a BEC (receiver battery eliminator circuit).
Posted on Thursday, May 20, 2010 • Category: Antennas
A modified version of the simple dipole is the folded dipole. It has two half-wave conductors joined at the ends and one conductor is split at the half-way point where the feeder is attached.
If the conductor diameters are the same, the feedpoint impedance of the folded dipole will be four times that of a standard dipole, i.e. 300 ohm.
The height above the ground
The height of an antenna above the ground, and the nature of the ground itself, has a considerable effect on the performance of an antenna.and its angle of radiation. See PROPAGATION
A dipole antenna can be arranged to operate on several bands using other methods. One way is to install "traps" in each leg.
Posted on Thursday, May 20, 2010 • Category: Power Supplies
This is a 1.2 - 12 V, max 1A power supply with a low voltage indicator LED. The indicator part incluedes three diodes and one LED. For example you are charging a battery, you can observe the charge status at that moment. Another advantage of this circuit, when the drawn current exceeds 1A (practically 0.85A), the current protector in LM317 intervens and LED indicator warns you about the very low output voltage.
Be careful while choosing the transformer. Most of the products are specified as 10VA but their outputs are not as said.
Another good property of this circuit is the mains noise does not pass to the DC part.
Posted on Thursday, May 20, 2010 • Category: Video
Digital VGA switch for switching between two PC monitors with MAX465 IC.
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