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In the early 1960s RCA brought out a transistor that was to become truly legendary: the 2N3055. With a pair of these devices, you could put together an audio power amplifier that could deliver a healthy 40 W into 8 Ω. The circuit described here is fully in tune with the spirit of that era. For example, there are only seven active components in each channel, which reflects the design simplicity typical of that era (and actually a timeless quality). This ‘retro’ power amplifier pumps 45 W into 8 Ω with an input signal level of 0.5 Vrms. It works as follows: the input signal is applied to the base of T1, while negative feedback from the output, attenuated by voltage divider R5/R6, is applied to the emitter of T1. The collector current of T1, which is proportional to the difference between the input and feedback signals, is fed to the base of T2. This transistor draws its operating current through R8 and R9 and provides voltage gain. Capacitor C6 is a bootstrap capacitor that hold the volta...

The essence of the circuit is for the input of tone and signal to provide an activation for the relay switch. Relay – an electrically operated switch where the current flowing through the coil of the relay is creating a magnetic field which attracts a lever and changes the switch contacts, thereby making its state open or close BC214 – a complementary silicon planar epitaxial transistor used in AF small signal drivers and am1 as well as for low noise preamplifier applications due to its feature of good linearity of DC current gain LM741 – a general purpose single operational amplifier with features such as offset null, compensated internal freq uency, voltage range with high input, good stability of temperature, and protected from short circuit The use of relay will allow the circuit to switch from one condition to another. It can also be referred to as a form of an electrical amplifier since it is able to control an output circuit of higher power than the input circuit. There are man...

The Chinese company Gionee, known mainly for its thinnest smartphone Elife S5.5 and Elife E5.1, is preparing another interesting device. The device, made in unusual for modern smartphones clamshell, was seen on the website of the Agency for certification of Chinese telecommunications equipment (TENAA). This model will be the world's first smartphone equipped with two screens with a resolution of 1080p. Diagonal inner and outer screens is 4 inches. Given the resolution of 1080 x 1920 pixels it gives quite a high density of 550 ppi. The device runs on Android 4.4 KitKat, built on a quad-core processor with a clock speed of 1.5 GHz, equipped with a 13-megapixel main and a 5-megapixel front-facing camera, 2 GB of RAM and 16 GB of internal memory and supports network LTE. The thickness of the model is 14.8 mm, and weight - 172 grams. While nothing is known about when to begin selling Gionee W900 . In any case, the smartphone will be released in China and it is difficult to say whether h...

This 16 LED Chaser Circuit Diagram is a double direction flash. Similar to Digital Ping- Pong 1, there is a movement of a lit dot, up and down along the LED's length. 16 LED Chaser Circuit Diagram When the D16 lit the situation changes and there is a reverse movement. Lit D15-14 ……D16, is lit making circles when the circuit is under power. The IC1 is an unstable flip- flop supplying with stable frequency pulses (the frequency can be changed by TR1, adjusting the velocity of the LED's up and down). This frequency supplies the IC3 (which is a 4-Bit UP and DOWN counter) through 2 gates A-B of the IC2. The output counter supplies the IC4 that is the driver of the LED's. The parts C- D of The IC2, make a R-S flip- flop, that changes situation, when the edge LED's D1 and D16 lit. We have an electronic limit for the situation change. In proportion the shape we make with the LED's, we can have the proportionate optional result, making various effects. Part List R1= 100Kohm...

Project Description This is a very easy to build power supply that is based on LM338 5A adjustable voltage regulator. I am using the supply for a long time, have no problem yet. Only current adjust is missing but I overcome this situation by using an LCD panel ampermeter.  There is no PCB for the circuit. I took a 3x16 copper plate and strip the unused areas by a knife. If you want you can use analog meters instead of LCD panels.    Notes Use thick wires for connections.When connecting the LM338 to the heatsink use thermal paste. Use external supplies for LCD panels. They can be 9V batteries. The panels I use draws 1mA current and the batteries last sufficiently long time. If you have small transformers which can supply regulated 9V, you can use them. You need separate transformers for each panel!The transformer should be 100 Watt but if you don't need high current you can try transformers that you already have. (I can draw 6A from 100Watt transformer.)If you have ...

Build a 250 to 5000 watts PWM DC/AC 220V Power Inverter  This is my schematic design of a Pulse Width Modulator DC/AC inverter using the chip SG3524 . I have built this design and using it as a backup to power up all my house when outages occur. If you like my work and intend to build the circuit don't forget to give me the 5 satrs :D and subscribe to me by clicking on the "follow" button so I know how many people benefit from the design, Thanks Notes: >The schematic circuit design is for a 250 watt output, while the pics are of my 1500 watts inverter that i built, to increase the power of the circuit you have to add more of the Q7 and Q8 transistors in parallel, each pair you add will increase your power by 250 watts, ex: to get 750 watts of power from the inverter you need to add in parallel 2 of Q7 and 2 of Q8 to the original design. >If you increase the power transistors you have to enlarge the T2 transformer to match the new needs, the c...

For cycling enthusiast Tom Donhou, there has only ever been one mission. To ride as fast as he possibly can on two wheels. In a bid to prove what can be achieved through backyard engineering, he has custom-built a bike which reached speeds of up to 80mph. A London-based bicycle frame builder by trade, Donhou invented a 104-tooth chainring to achieve the goal. And in another tribute to British engineering, he wanted to use a car to block the wind to reduce wind traction. The current land speed record for a bike (not bycycle) is 167mph which was set by Fred Rompelberg using a dragster in the Salt Flats.[via]

    The Nexus 6 would have a 5.9 inch screen with QHD resolution (2K), 13 megapixel camera with optical image stabilizer and a metal frame and the new version Android L. The Google phone, Nexus, will continue to grow after all Nexus 6 and come with a 5.9 inch screen, multiple rumors say. Although the photo is an image (render) created by Android Police, every detail which is present in this Nexus 6 has been based on rumors you've heard the blog and that have circulated on the Internet. According to AP, the official name of the new Google phone, manufactured by Motorola, Nexus 6 (Shamu) and would be called based on the new Moto X design, but in a larger size, black front speakers and a metal frame around cell. The back of the Nexus 6 include a 13 megapixel camera with optical image stabilization, dual flash, 3200mAh + battery, a front 2-megapixel camera and QHD (2K) screen. With these reports on the Nexus 6 hope this be a new cell showed both is size and its features and compon...

The power line fluctuations and cut-offs cause damages to electrical appliances connected to the line. It is more serious in the case of domestic appliances like fridge and air conditioners. If a fridge is operated on low voltage, excessive current flows through the motor, which heats up, and get damaged. The under/over voltage protection circuit with time delay presented here is a low cost and reliable circuit for protecting such equipments from damages. Whenever the power line is switched on it gets connected to the appliance only after a delay of a fixed time. If there is hi/low fluctuations beyond sets limits the appliance get disconnected. The system tries to connect the power back after the specific time delay, the delay being counted from the time of disconnection. If the power down time (time for which the voltage is beyond limits) is less than the delay time, the power resumes after the delay: If it is equal or more, then the power resumes directly. This circuit has been desig...

The SCC2 is a solar charge controller, it’s function is to regulate the power flowing from a photovoltaic panel into a rechargeable battery. It features easy setup with one potentiometer for the float voltage adjustment, an equalize function for periodic overcharging, and automatic temperature compensation for better charging over a range of temperatures. 10 Amp Solar Charge Controller Circuit Diagram With Parts List The goal of the circuit design was to make a charge controller with analog simplicity, high efficiency, and reliability. A medium power solar system can be built with a 12V solar panel up to 10 amps, the SCC2, and a lead acid or other rechargeable up to a few hundred amp hour capacity. The SCC2 can be operated at battery voltages other than 12V, it can work at 6V and 24V by changing a few parts. Operation at voltages between 6V and 24V is also possible. Specifications Maximum solar panel current: 10 Amps Night time battery drain current: approximately 1ma Nominal battery v...

Google has introduced a modular smartphone Project Ara Spiral 2. At the conference for developers Google Project Ara Developers Conference a world-renowned search giant officially introduced its first commercial prototype of a modular smartphone project Project Ara. The novelty is called Project Ara Spiral 2. The device has received from the manufacturer display with a resolution of 720x1280 pixels and two 64-bit processor - 4-core Marvell PXA1928 clocked at 1.5 GHz and graphics Vivante GC5000, and 6NVIDIA Tegra K1 with two cores and graphics ARMv8 Nvidia Kepler, which has a top speed of 2.5 GHz. The "initial" set of modular Project Ara Spiral 2 also includes battery, speaker, 5MP camera, and wireless modules 3G, Wi-Fi and Bluetooth. The smartphone has a fairly simple design that allows its user immediately after the purchase of their own modules to change it, of which there are at present more than 30. Sales of Google Project Ara Spiral 2 will start in the second half of 201...

A simple motorcycle battery over discharge protector circuit is explained in the following post. The circuit will prevent the battery from over discharging by the motorcycle headlamp whenever the mo-bike alternator is not enabled or is idling in the neutral mode in which case the battery is normally subjected to excess loads via the headlamp bulb. Motorcycle batteries are normally a lot smaller with their sizes and ratings compared to the vehicle and the usage. The main use of the battery present in mo-bikes is for enabling electronic start through a press of the given start button. However this small sized battery also has to undergo further stresses while operating excess loads such as the horn, the indicator lights, the tail light and the brake light. Even though the above loads mostly tend to depend on the motorcycles battery power, these do not affect the battery charge level significantly. The one that truly affects the battery is the motorcycle headlamp, which when switched O...

Circuit with RC Elements Fig. Basic circuit diagram: RC element Advantage: 1) Limit the spike to low levels and also limits dv/dt. 2) Can be used for AC & DC contactor Note: Very careful selection of resistance & capacitance is required to achieve desired switching time of contactor Fig. 3: contactor with RC Element ........

Usb series player is an electronic device or electronic circuit that functions as an MP3 player that is stored on a storage device such as USB flash. In this usb circuit using an IC as a modifier of digital voice data into analog so that it can be applied to a headphone, or again through the power amlplifier strengthened so that it can be heard through the speakers. IC used in this circuit using IC PCM2902 as a modifier of a digital data into analog data storage. Below is a schematic diagram of a USB player. Schematic usb player