Group items tagged

Driver Smith - Best Converting Driver Update Product.

This is circuit 13.8V, 40A Switching Power Supply,It is high current power supply switching regulator.And Nice Circuit for power user. This article was originally published (in a slightly modified form) in the QST magazine, December 1998 and January 1999, and in the Radio Amateur's Handbook, 1999. Visit the American Radio Relay League for information on these publications, and a world of ham radio related things! Design decisions There are several different topologies for switchers in common use, and the first decision a designer must take is which of them to consider. Among the factors affecting the decision are the power level, the number of outputs needed, the range of input voltage to be accepted, the desired tradeoff between complexity, quality and cost, and many more. For this power supply I decided to use the half bridge forward converter design. This topology connects the power transformer to a bridge formed by two power transistors and two capacitors. It is reasonably simple, puts relatively low stress on the power transistors, and makes efficient use of the transformer's magnetic capabilities.The second basic decision is which switching frequency to use. The present trend is to use ever higher frequencies. But by doing so it becomes more difficult to filter out the RF noise inevitably generated by the switching. So I decided to stay at a low switching frequency of only 25 kHz for the full cycle, which due to the frequency doubling effect of the rectifiers results in 50 kHz on the output filter. For the main switching elements, bipolar transistors or MOSFETs can be used. Bipolars have lower conduction losses, while MOSFETs switch faster. As in this design I wanted to keep the RF noise at an absolute minimum, very fast switching was not desired, so I used bipolar transistors. But these tend to become too slow if the driving is heavier than necessary. So, if the transistors have to switch at varying current levels, the drive to them must also be varied. This is called proportional driving, and is used in this project. The half bridge converter is best controlled by pulse width modulation. There are several ICs available for this exact purpose. I chose the 3524, which is very simple to use and easy to find. Any 3524 will do the job. It can be an LM3524, SG3524, etc. This basically ends the big decisions. From now on, designing the circuit is a matter of calculating proper values for everything.

This HD TV UHF wideband amplifier(Ultra High Frequency amplifier) has a total gain of 10 to 15 dB in the 400 – 850 MHz domain frequency so it can be used where the tv signal is weak. For this UHF antenna tv amplifier to work correctly you need to cut the components pins as short as possible. C1, C2, C6, C7 are SMD type ( surface mounted ). This antenna tv amplifier or uhf wideband amplifier need to be build inside of a metal box and then connected close to the tv antenna. Prototype pictures (Prototip resimler) Antenna HD TV UHF band amplifier circuit schematic (Anten HD TV UHF bandındaki amplifikatör devre şeması) PCB layout for Wideband HD TV UHF Antenna TV Amplifier Circuit using transistor 2sc3358 (Baskı Devresi) The power supply is a simple 12V stabilized source. The antenna tv amplifier can be connected directly to the power supply thru coaxial cable of the tv antenna but you need a 10 – 100uH coil on the alimentation line. The tv set will be connected to the uhf amplifier thru a small coupling capacitor. Adjusting is easy, just bring the P1 to the middle and then adjust it untill you obtain the best tv image quality. Digital Tv antenna UHF amplifier components (Devrede kullanılan malzeme listesi): T1 -Transistor 2sc3358C1 – 10µF/35vC2,C9 – 1nFC3 ,C4 – 10nFC5,c6,c7,c8 – 10pFR1 – 470 OhmsR2 – 2.2 KR3 – 1KohmsP1 – 5KohmsL1,L2 – 2 turns 22AWG , 3mm Ø.L3,L4 – 10uH or 10 turns, 0.2mm Ø on ferrite..12 volts special power supply. 2sc3358 Transistörü kullanılarak Geniş Bant DTV UHF Anten TV Amplifikatör Devresi