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Using the MAX8844 lithium ion charger IC released by Maxim Semiconductors you can design an very simple and efficiency charger circuit for charging a single cell lithium-ion battery . The MAX8844 lithium ion charger integrate a current-sense circuit, MOSFET pass element, thermal-regulation circuitry, and eliminate the external reverse-blocking Schottky diode to create the simplest and smallest charging solutions for handheld equipment. Lithium ion Charger Circuit diagram Also , using this charger solution the power source is optimized by the MAX8844Z using automatically select function between the USB or IN power source but if are both power sources connected the highest priority is for IN power source to ensure the shortest charging time for the system . The MAX8844 charger chip accept an input voltages range from 4.25V to 28V (IN and USB), but the charging is disabled if the input voltage exceeds +7.5V for protection against unqualified or faulty AC adapters. These charger IC is very...

Laser torch-based burglar alarms normally work in darkness only. But this long-range photoelectric alarm can work reliably in daytime also to warn you against intruders in your big compounds, etc. The alarm comprises laser transmitter and receiver units, which are to be mounted on the opposite pillars of the entry gate. Whenever anyone enters to interrupt the transmitted laser beam falling on the receiver, the buzzer in the receiver circuit sounds an alarm. The range of this burglar alarm is around 30 metres, which means you can place the transmitter and the receiver up to 30 metres apart. Since the laser torch can transmit light up to a distance of 500 metres, this range can be increased by orienting the phototransistor sensor properly. To avoid false triggering by sunlight, mount the phototransistor sensor such that it doesn’t directly face sunlight. Long-range Burglar Alarm Using Laser Torch Fig. 1: Circuit of laser torch based transmitter The transmitter circuit is powered by 3V DC...

This  Emergency lighting using white LEDs Circuit Diagram should be assembled only by experienced people and it is advisable to use a protection network, which can be a light bulb in series. For anyone who is thinking of making a system of emergency lighting and simple, this circuit is a cheap and functional output. The circuit is basically composed of a source AC / DC without a transformer, a charger, a system of automatic switching using a diode and a diode switch to change the brightness.  Emergency lighting using white LEDs Circuit Diagram List of Components R1 = 1M, ¼ Watt, 5% R2 = 10K, ¼ Watt, 5% R3 = 10 Ohms 1Watt All resistors are LED = 22 Ohms, ¼ Watt C1 = 205/400V, PPC C2 = 100uF, 25V Z1 = 9 V, 1 WATT T1 = BD 140 All diodes = 1N4007 BATTERY = 6 volts 4 AH LEDS = WHITE, HIGH EFFICIENCY, 5mm

The 30 watt amplifier schematic shown below provides an appropriate power boost with an input of 4 watt up to 6 watts. The circuit is designed to cover 88-108MHz FM Broadcast Band. However, the circuit is very stable at my place and provides a clean-output through seven (7) element Butter-worth low-pass filter. Circuit Diagram: Notes: The heart of the circuit is 2SC1946A VHF RF power transistor. The transistor is specifically designed for operation in frequencies up to 175 MHz, with very good results. As you can see, the power line is well decoupled. The amplifier current can be over 5 amps. All the coils are made from 16gauge laminated wire (or Silver copper wire can do best) and the RFC can be of HF toroid core (as shown in the picture) or 6 holes ferrite bead.C3 and R1 forms snubber circuit while R2 and C6 prevent the amplifier from self-oscillation at VHF, sometimes you need to add 180 ohms in parallel with L7.That will cause the amplifier to dissipate UNDESIRABLE VHF thereby r...

The following post explains a very simple yet safe Li-Ion battery charger circuit using just a single IC LP2951. Unlike lead acid batteries one good thing about the Li-Ion batteries is that they can be charged at 1C rate initially. It means the charging current may be as high as the rated AH of the battery at the onset. The design presented in this article can be used for charging a single 3.7V Li-ion cell or a standard cell phone battery externally at a relatively slower rate. The diagram depicts a configuration which was used for charging a Li-Ion cell of a portable stereo unit. The charging specification of the circuit may be summarized as under: Maximum charging current = 150mA Full charge volt = 4.2V +/- 0.025V Charge Current = set at current limit charge mode.    In the given circuit the IC LP2951 becomes the main active component which has been specifically chosen because it is capable of delivering an output voltage that's very stable over temperature. The...

This audio amplifier circuit is based on the TDA1519 amplifier ic which can be used in audio applications which don’t need high output power .The TDA1519 circuit can deliver 2x6 watts output power . Audio Amplifier Circuit Using TDA1519 TDA1519 is an integrated class-B dual output amplifier in a 9-lead single in-line (SIL) plastic medium power package is primarily developed for car radio applications.This amplifier electronic circuit project needs to be powered from a 14.4 volt DC power supply

A 6 watt audio amplifier circuit using TDA2613 is shown here. TDA2613 is an integrated Hi-Fi  audio amplifier IC from Philips Semiconductors. The IC is switch ON / switch OFF click proof, short circuit proof, thermally protected and is available in 9 pin single in line plastic package. In the given circuit, TDA2613 is wired to operate from a single supply. Capacitor C4 is the input DC decoupler while capacitors C5, C6 are power supply filters. Input audio is fed to the non inverting input through capacitor C4. Inverting input and Vp/2 pins of the IC are tied together and connected to ground through capacitor C3. Capacitor C2 couples the speaker to the ICs output and the network comprising of capacitor C1 and resistor R1 improves the high frequency stability. . Reliable 6 Watt Hi Fi Audio Amplifier Circuit diagram Notes. Assemble the circuit on good quality PCB. Supply voltage (Vs) can be anything between 15 to 24V DC. Heat sink is necessary for TDA2613. Do not give more than 24V to...

A 6 watt audio amplifier circuit using TDA2613 is shown here. TDA2613 is an integrated Hi-Fi  audio amplifier IC from Philips Semiconductors. The IC is switch ON / switch OFF click proof, short circuit proof, thermally protected and is available in 9 pin single in line plastic package. In the given circuit, TDA2613 is wired to operate from a single supply. Capacitor C4 is the input DC decoupler while capacitors C5, C6 are power supply filters. Input audio is fed to the non inverting input through capacitor C4. Inverting input and Vp/2 pins of the IC are tied together and connected to ground through capacitor C3. Capacitor C2 couples the speaker to the ICs output and the network comprising of capacitor C1 and resistor R1 improves the high frequency stability. Reliable 6 Watt Hi Fi Audio Amplifier Circuit diagram Notes. Assemble the circuit on good quality PCB. Supply voltage (Vs) can be anything between 15 to 24V DC. Heat sink is necessary for TDA2613 . Do not give more than 24V ...

This Selector Antennas using PIN Diodes Circuit Diagram selector antennas uses PIN diodes, was designed using common components and is very useful when used various external antennas, this antenna selector uses PIN diodes that eliminate disadvantages of mechanical switches especially at high frequency.  Capacitors C1 to C4 and C9 are used to prevent the input and output circuit DC. Shock L1 to L5 prevent leakage of HF signal.Shock L1 to L5 can be wound on a ferrite core, using enameled copper wire of 0.3 mm in diameter, two rounds will suffice for entries for VHF and UHF 5 (1 mH is required for VHF and UHF about 5 uH). The circuit was designed for antenna input impedance of 50 or 75 ohms. Selector Antennas using PIN Diodes Circuit Diagram

ET-5EC-K04/ET-5EC-K61/ET-5EE-K06 (Tuner) – TDA8897/TDA8899 (System control chroma jungle) – STR W6556A – LA78041/TDA8177 (Vertical scan output) – TA1343 (Audio processor) – AN7522/AN17821 (Audio output) – 24C08 (System memory) Circuit Diagram [Click on the circuit diagram to zoom in]

This is a small adjustable clock/date with thermometer function based on PIC16F628 or PIC16F84 microchip and DS18S20 or DS18B20 temperature sensor. The hardware part is very simple because it only uses a pic microcontroller, the DS18S20/DS18B20 sensor, 4x7 segments (common anode, something like KW4-301xxx Series, or common cathode something like CC56-21SURKWA), four transistors, some rezistors! When you first power the device the clock is mentained for 8 seconds. Then the date for 2 seconds and temperature will be displayed for 3 seconds. The clock has four buttons, with one button you enter in set mode, with another button you increase values, the third button will be used to decrease values and you can put or not, the reset. If you don't want a reset button just connect the pin to +5V. You can change: ho -> hour, from 0 to 23 nn -> minutes, from 0 to 59 (I could not display m so I used n twice for it) dd -> date day, from 1 to days/month -> calculated based on month...

This Electronic circuit Project a very interesting  split power supply circuit can be constructed using this schematic diagram which is based on a LM380 audio power IC . The regulation of the output voltage depends of the upon circuit feeding the LM380 . The power dissipation is around 1 watt so an small heatsink may be required . If the power dissipation is exceeded , the device will go into thermal shut-down protection . Split Power Supply Circuit Diagram: Current limiting occurs if the output current exceeds 1.3 A  . The R1 linear potentiometer is , should be initially set to mid level  , is used nullify any imbalance in the output . This split power supply circuit should not be used for input voltages which exceed 20 volts . Use this circuit after a regulated power supply circuit , but try to keep the specifications for the maximum rating of this split voltage circuit .

Using the LTC3112 fixed frequency synchronous buck-boost DC DC can be designed a very simple high efficiency, high power led driver electronic project .The unique 4-switch, single inductor architecture of the LTC3112, provides low noise and seamless operation from input voltages above, below or equal to the output voltage.With an input range of 2.7V to 15V, the LTC3112 is well suited for a wide variety of single or multiple cell battery, backup capacitor or wall adapter source applications . Circuit Diagram The LTC3112 features selectable PWM or Burst Mode operation, an easily synchronized oscillator and output disconnect in shutdown. An output current monitor circuit allows the load current to be controlled or measured.Other features of the LTC3112 DC DC converter include : <1 br="br" current="current" short="short" shutdown="shutdown">circuit protection, soft-start, current limit and thermal shutdown. As you can see in the circuit diagram...

This is a 200 Watt Amplifier Circuit Diagram that uses a TDA2030 IC which is an audio power amplifier 200 watt low cost. The 200 watts can be achieved with a load impedance of 4 ohms. The TDA2030 can typically provide up to 14 watts into a 4 ohm load, but if used in bridge mode and we use some cheap power transistors we can get to 200 watt. The design of this amplifier circuit 200 watt audio is very simple and requires few external components. For best performance, you can use a source of 28 volts (+ / - 14 volts), not more than 44 volts (+ / - 20 volts).  As you can see in the diagram, for this power amplifier circuit you need high capacity capacitors and a power supply high current. All transistors and ICS should be mounted on a heat sink to prevent damage by temperature. For small value resistors (1 ohm, 2.2 ohm) resistors use 2-5 watts.  200 Watt Amplifier Circuit Diagram using TDA2030

This 30v variable power supply circuit is based on LM317  voltage regulator circuit . This LM317 30v variable power supply circuit can deliver high current (around 5 amps) and variable output voltage between 1.2 volts, up to 30 volts. The led D3 mounted on pin 6 at lm301 lights in constant current mode . 30V Variable Power Supply Using LM317 Circuit diagram  Current limit can be adjusted using R2 potentiometer and the output voltage can be adjusted from 1.2 volts to 30 volts using R8 potentiometer . Input voltage for this variable power supply must be around 35 volts .For this power supply circuit you need to use LM317K circuit (in to3 package ) which must be mounted on a heatsink .

Hi everyone! First of all I would like to thank Avinash Gupta for writing all the valuable tutorials and libraries for AVR Microcontrollers and helping people like me to build projects and learn new things. I am dedicating this post to him!   Introduction: Using remote keys from 1 to 4, you can control 4 appliances. You can easily extend this number to as many you wish. For example, if you press key_1 on your remote, fan will turn ON. If you press the same key again, fan will turn OFF i.e each time you press a key configured for an appliance, the condition will toggle. I have programmed the MCU such that all devices will turn OFF on pressing power button(RED COLOR on top of your remote). You can also choose combinations like turning all fans OFF at a time, etc. With little tweaking, you can change the program yourself! The status of the appliances is shown in an LCD. You can ignore this feature if you dont want LCD. I used LCD for developing the code. I main advantage in this project ...