Tuesday, February 4, 2014
Super Boost 3 6A USB Charger Based on LM2700
This design is inspired by the Minty Boost but it fixes some of the issues that I had with it. The Minty Boost is limited to 600mA due to the LT1302 chip. The Super Boost uses the LM2700 which can push up to 3.6A. This will enable i-devices to draw up to there maximum of 1A which will enable a faster recharge.
Saturday, January 11, 2014
Under this circumstance cell phone jammer should be packed well
Under this circumstance, cell phone jammer should be packed well.
In 1999, the Groups industrial sales revenue of 21.5 billion yuan. In August 1997, Haier was the State Economic and Trade Commission identified as one of the six first technological innovation pilot enterprises, focusing on supporting the impact of the worlds top 500. "Difficult first" strategy, insist on playing the Haier brand exports, Haier is now 62 dealers in overseas development, more than 36,000 distribution points, products exported to the worlds top ten economic regions in Europe, America, Middle East, Southeast Asia 90 countries and regions, 1999, Haier brand export $ 138 million. Has five factories overseas, in the construction of eight, toward the the goal of the internationalization of enterprises. In April 1999, the trinity of Haier was set up on the road of internationalization, Haier has taken a solid step forward. Actually, the inspection process of the raw material of cell phone jammer is the vital and complicated process.
In 1997, the United States "appliance" magazine published the worldwide fastest growing home appliance business, Haier than GE, Siemens and other world famous, top of the list. March 25, 1998, Haier Group CEO Zhang was invited to board the Harvard University forum, "Haier culture activate the shock fish" cases formally written into the Harvard University teaching materials, marking Haier real to the world. November 30, 1998, the British "Financial Times" reported: in the companies rating the reputation of the Asia-Pacific region, Haier ranked seventh, is the only top ten Chinese enterprises. In 1999, the U.S. magazine "Fortune" to "the power of Chinas Haier much coverage of the results obtained by the title of the Haier Group. The inspector should check the rigidness, appropriateness of the raw material of cell phone jammer .This kind of design of cell phone jammer is the systematic study on the above problems
99 Fortune Forum in Shanghai conference Haier Group Zhang president as the sole participation of a Chinese home appliance entrepreneurs and make a speech. December 7, 1999, the British "Financial Times" published the worlds 30 most respected entrepreneurs ranking Haier CEO Zhang Ruimin Rong, ranked 26, which is the highest reputation of Chinese entrepreneurs worldwide. To speed up the enterprises to enter the worlds top 500 pace, the completion of the Haier "three parks, one school", the three parks Haier Development Zone Industrial Park, Haier Information Park, Haier Park, a school Haier University Department. June 25, 1999, the General Secretary Jiang Zemin visited Haier, when listening to Zhang reported by the President of Haiers goal is to enter the worlds top 500, said happily: "I look completely. The manufacture process of cell phone jammer should also be strictly controlled.
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In 1999, the Groups industrial sales revenue of 21.5 billion yuan. In August 1997, Haier was the State Economic and Trade Commission identified as one of the six first technological innovation pilot enterprises, focusing on supporting the impact of the worlds top 500. "Difficult first" strategy, insist on playing the Haier brand exports, Haier is now 62 dealers in overseas development, more than 36,000 distribution points, products exported to the worlds top ten economic regions in Europe, America, Middle East, Southeast Asia 90 countries and regions, 1999, Haier brand export $ 138 million. Has five factories overseas, in the construction of eight, toward the the goal of the internationalization of enterprises. In April 1999, the trinity of Haier was set up on the road of internationalization, Haier has taken a solid step forward. Actually, the inspection process of the raw material of cell phone jammer is the vital and complicated process.
In 1997, the United States "appliance" magazine published the worldwide fastest growing home appliance business, Haier than GE, Siemens and other world famous, top of the list. March 25, 1998, Haier Group CEO Zhang was invited to board the Harvard University forum, "Haier culture activate the shock fish" cases formally written into the Harvard University teaching materials, marking Haier real to the world. November 30, 1998, the British "Financial Times" reported: in the companies rating the reputation of the Asia-Pacific region, Haier ranked seventh, is the only top ten Chinese enterprises. In 1999, the U.S. magazine "Fortune" to "the power of Chinas Haier much coverage of the results obtained by the title of the Haier Group. The inspector should check the rigidness, appropriateness of the raw material of cell phone jammer .This kind of design of cell phone jammer is the systematic study on the above problems
99 Fortune Forum in Shanghai conference Haier Group Zhang president as the sole participation of a Chinese home appliance entrepreneurs and make a speech. December 7, 1999, the British "Financial Times" published the worlds 30 most respected entrepreneurs ranking Haier CEO Zhang Ruimin Rong, ranked 26, which is the highest reputation of Chinese entrepreneurs worldwide. To speed up the enterprises to enter the worlds top 500 pace, the completion of the Haier "three parks, one school", the three parks Haier Development Zone Industrial Park, Haier Information Park, Haier Park, a school Haier University Department. June 25, 1999, the General Secretary Jiang Zemin visited Haier, when listening to Zhang reported by the President of Haiers goal is to enter the worlds top 500, said happily: "I look completely. The manufacture process of cell phone jammer should also be strictly controlled.
Friday, January 10, 2014
25 Metres Range Short Wave AM Transmitter
Here the short wave AM Transmitter circuit design diagram. The circuit is quite simple and easy to build since it applies only a few electronic components. The primary feature of this transmitter is that it really is absolutely free from the LC (inductor, capacitor) tuned circuit and runs using a fixed frequency of 12 MHz that is very stable. An LC based tuned circuit is inherently unstable because of drift of resonant frequency due to temperature and humidity variations.
25 Metres Range, Short Wave AM Transmitter Circuit diagram :
Resistors R1 and R2 are utilized for DC biasing of transistor T1. The capacitor C1 gives coupling in between the condenser microphone and the base of transistor T1. In the same way, resistors R3, R4 and R5 give DC biasing to transistor T2.
The oscillator segment is a combination of transistor T2, crystal XTAL, capacitor C2, C3 and resistors R3, R4 and R5. The crystal is excited by a portion of energy from the collector of transistor T2 via the feedback capacitor C2. The crystal vibrates at its essential frequency and the oscillations happening because of the crystal are placed to the base of transistor T2 across resistor R4. Using this method, continuous undamped oscillations are acquired. Any crystal having the frequency in short wave range could be substituted in this circuit, even though the operation was tried using a 12 MHz crystal.
The Transistor T1 has 3 capabilities:
- The transistor features the DC path for extending +VCC source to transistor T2.
- It amplifies the audio signals which is generated by condenser mic.
- It injects the audio signal into the high frequency carrier signal for modulation.
The transmitted signals could be received on any short wave receiver without having distortion and noise. The range of this transmitter is 25 to 30 metres and may be expanded even more in case the length of the antenna wire is suitably extended together with good matching.
Simple Unipolar to Dual Supply Converter Circuit Diagram
Simple Unipolar to Dual Supply Converter Circuit Diagram. 817V The outputs in this circuit are independently variable and can be loaded unsymmetrically. The output voltage remains constant, irrespective of load and changes. By varying potentiometers R2 or R6, the output voltages can be conveniently set. Outputs can be varied between 8 and 17 V, so that the standard ±9, ±12, and ±15 V settings can be made.
Unipolar to Dual Supply Converter Circuit Diagram
This converter is designed for a maximum load current of 1 A and the output impedance of both supplies of 0.35 0. This circuit is not protected against shortcircuits, but uses the protection provided by the de input source. This circuit is ideal for biassing operation amplifier circuits.
Friday, December 27, 2013
Build a 10 Amp 13 8 Volt Power Supply Circuit Diagram
Sometimes amateurs like to home-brew their power supplies instead of purchasing one off the shelf at any of the major ham radio retail dealers. The advantage to rolling your own power supply is that it teaches us how they work and makes it easier to troubleshoot and repair other power supply units in the shack. It should be noted that there is no real cost advantage to building your own power supply unless you can get a large power transformer and heat sink for a super low price.
Of course rolling our own gives us the ability to customize the circuit and make it even more reliable than commercial units. The circuit in Figure 1 will give us 10 amps (12 amps surge) with performance that equals or exceeds any commercial unit. The circuit even has a current limiting feature which is a more reliable system than most commercial units have. Just like other commercial units, this circuit uses the LM723 IC which gives us excellent voltage regulation. The circuit uses 3 pass transistors which must be heat sinked. Resistor R9 allows the fine tuning of the voltage to exactly 13.8 volts and the resistor network formed by resistors R4 through R7 controls the current limiting.
The LM723 limits the current when the voltage drop across R5 approaches .7 volts. To reduce costs, most commercial units rely on the HFE of the pass transistors to determine the current limiting. The fault in that system is that the HFE of the pass transistors actually increases when the transistors heat up and risks a thermal runaway condition causing a possible failure of the pass transistors. Because this circuit samples the collector current of the pass transistors, thermal runaway is not a problem in this circuit making it a much more reliable power supply.
The only adjustment required is setting R9 to the desired output voltage of anywhere between 10 and 14 volts. You may use a front panel mounted 1K potentiometer for this purpose if desired. Resistor R1 only enhances temperature stability and can be eliminated if desired by connecting pins 5 and 6 of IC-1 together. Although it really isn’t needed due to the type of current limiting circuit used, over voltage protection can be added to the circuit by connecting the circuit of Figure 2 to Vout. The only way over voltage could occur is if transistors Q2 or Q3 were to fail with a collector to emitter short. Although collector to emitter shorts do happen, it is more much more likely that the transistors will open up when they fail.
10 Amp 13.8 Volt Power Supply Circuit Diagram
I actually tested this and purposely destroyed several 2N3055’s by shorting the emitters to ground. In all cases the transistors opened up and no collector to emitter short occurred in any transistor. In any event, the optional circuit in Figure 2 will give you that extra peace of mind when a very expensive radio is used with the power supply. The circuit in Figure 2 senses when the voltage exceeds 15 volts and causes the zener diode to conduct. When the zener diode conducts, the gate of the SCR is turned on and causes the SCR to short which blows the 15 amp fuse and shuts off the output voltage.
A 2N6399 (Tech America) was used for the SCR in the prototype but any suitable SCR can be used. While over voltage protection is a good idea, it should not be considered a substitute for large heat sinks. I personally feel the best protection from over voltage is the use of large heat sinks and a reliable current limiting circuit. Be sure to use large heat sinks along with heat sink grease for the 2N3055 transistors. I have used this power supply in my shack for several months on all kinds of transceivers from HF, VHF to UHF with excellent results and absolutely no hum. This power supply will be a welcome addition to your shack and will greatly enhance your knowledge of power supplies.
Parts
R1 1.5K ¼ Watt Resistor (optional, tie pins 6 & 5 of IC1 together if not used.)
R2,R3 0.1 Ohm 10 Watt Resistor (Tech America 900-1002)
R4 270 Ohm ¼ Watt Resistor
R5 680 Ohm ¼ Watt Resistor
R6,R7 0.15 Ohm 10 Watt Resistor (Tech America 900-1006)
R8 2.7K ¼ Watt Resistor
R9 1K Trimmer Potentiometer (RS271-280)
R10 3.3K ¼ Watt Resistor
C1,C2,C3,C4 4700 Microfarad Electrolytic Capacitor 35 Volt (observe polarity)
C5 100 Picofarad Ceramic Disk Capacitor
C6 1000 Microfarad Electrolytic Capacitor 25 Volt (observe polarity)
IC1 LM723 (RS276-1740) Voltage Regulator IC. Socket is recommended.
Q1 TIP3055T (RS276-2020) NPN Transistor (TO-220 Heat Sink Required)
Q2,Q3 2N3055 (RS276-2041) NPN Transistor (Large TO-3 Heat Sink Required)
S1 Any SPST Toggle Switch
F1 3 Amp Fast Blow Fuse
D1-D4 Full Wave Bridge Rectifier (RS276-1185)
T1 18 Volt, 10 Amp Transformer Hammond #165S18 (Tech America 900-5825)
R1 1.5K ¼ Watt Resistor (optional, tie pins 6 & 5 of IC1 together if not used.)
R2,R3 0.1 Ohm 10 Watt Resistor (Tech America 900-1002)
R4 270 Ohm ¼ Watt Resistor
R5 680 Ohm ¼ Watt Resistor
R6,R7 0.15 Ohm 10 Watt Resistor (Tech America 900-1006)
R8 2.7K ¼ Watt Resistor
R9 1K Trimmer Potentiometer (RS271-280)
R10 3.3K ¼ Watt Resistor
C1,C2,C3,C4 4700 Microfarad Electrolytic Capacitor 35 Volt (observe polarity)
C5 100 Picofarad Ceramic Disk Capacitor
C6 1000 Microfarad Electrolytic Capacitor 25 Volt (observe polarity)
IC1 LM723 (RS276-1740) Voltage Regulator IC. Socket is recommended.
Q1 TIP3055T (RS276-2020) NPN Transistor (TO-220 Heat Sink Required)
Q2,Q3 2N3055 (RS276-2041) NPN Transistor (Large TO-3 Heat Sink Required)
S1 Any SPST Toggle Switch
F1 3 Amp Fast Blow Fuse
D1-D4 Full Wave Bridge Rectifier (RS276-1185)
T1 18 Volt, 10 Amp Transformer Hammond #165S18 (Tech America 900-5825)
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