Circuit-Zone.com - Electronic Projects
Posted on Thursday, January 27, 2011 • Category: FM Transmitters
Everyone involved with radio transmitters needs some instruments to assess basic antenna functionality. Among these instruments, the best-known and most-used one is the Standing Wave Ratio meter. Some radio amateurs develop a cult for these little gadgets, having them in line all the time and watching the needles bounce while they chat. I have seen some guys owning 5 or 6 SWR meters, and no other instrument relating to antenna testing! While it's unfortunate that some people - specially amateurs - assign so much importance to SWR and so little to other parameters, it's also a fact that SWR needs to be known, so if you use transmitters, you need an SWR meter.
Posted on Thursday, January 27, 2011 • Category: Amplifiers
The following is a 70W amplifier based on a popular TDA7294 chip. Main technical characteristics of the amplifier are as follows: input resistance - 22 kOhm input voltage - 750 mV nominal output power at 4 ohms and THD 0.5% - 70 Watts Frequency Range - 20 ... 20000 Hz supply voltage - ± 27 V, quiescent current - 60 mA. The amplifier has a built-in thermal protection, and protection against overload and short circuit in the load. For "soft" switching amplifier is SA1. Switch can be powered from a bipolar unregulated power supply. Power AC Transformer - 250-A, the secondary winding should be designed to current than 5A.
Posted on Thursday, January 27, 2011 • Category: Power Supplies
With a maximum capacity of 20 volts and 1 amp, it will supply most of your projects, it's greatest quality is the protection all your projects, it is capable of limiting the maximum current to as low as 1mA, saving your ICs and transistors in case of an accidental short circuit during the experimenting period of your projects. It is also an excellent battery charger.
Posted on Wednesday, January 26, 2011 • Category: FM Transmitters
Be "On Air" with your own radio station! BA1404 HI-FI Stereo FM Transmitter - Special Edition Kit is an exciting transmitter that will broadcast high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground. Add 500mW FM / VHF Transmitter Amplifier / Booster
for even longer range.
Special Edition BA1404 HI-FI Stereo FM Transmitter Kit includes premium components with audio grade gold capacitors, 1% Metal Film Resistors and quality PCB with Red Solder Mask and Plated-Through Holes. The kit is based on the popular BA1404 stereo broadcaster IC which contains all the complex circuitry for generating the stereo FM signal. 38 KHz crystal provides a rock solid stability of sub-carrier for stereo signal.
Posted on Wednesday, January 26, 2011 • Category: Power Supplies
As you might expect, I have several power supplies that have more than enough capacity to power my new KN-Q7 transceiver. However, my largest power supply is normally connected to my main 100W PEP SSB transceiver. It is capable of 20A and more, but it’s not easy to connect other equipment to it. I also have a smaller 8A power supply, but I use this to power some other VHF and UHF transceivers.
In short, I wanted a simple power supply which I could dedicate to this new transceiver.
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