Electronic Circuits and Diagram-Electronics Projects and Design

Buck Boost converter circuit using LTC3440 Description. A very efficient buck boost converter circuit is shown here. The circuit is based on the LTC3440 buck boost regulator IC from Linear Technology. The LTC3440 requires only one inductor and provides up to 96% efficiency. There is no need of Schottky diode for applications where output voltage is less than 4.3V and the IC can deliver up to 600mA output current. In the circuit the IC is wired as a buck boost regulator providing 3.3V output from a 2.7 to 4.2V input. R1 is the timing resistor which determines the oscillator frequency…

Voltage Converter Circuit – 6 to 12 volts One of our valuable readers asked us about any other application of the Audio amplifier IC TDA2003. Well, it can be used to build a Voltage converter circuit. Here’s an example of 6 to 12 volts converter using the same IC Description of the Voltage converter circuit: Two TDA2003 ICs are used here which are wired as oscillators and their outputs are identical but 180 out of phase. Capacitors C3 and C6 determine the frequency of these oscillators respectively. When the output of IC1 is low capacitor C1 charges to the supply…

12 volt DC Power Supply from USB port The circuit given below infact is a 5 volt to 12 volt converter. It uses the 5 Volts from USB port and converts it to 12 volts DC with the help of IC LT1618. Description : Using this circuit we can convert 5V DC from the computer USB port to 12V DC and a circuit like this will find a lot of application in USB powered systems. The heart of this circuit is IC LT1618 which is a constant current, constant voltage boost converter. The IC has a wide input voltage range…

Dual Power Supply using LM 320 and LM 340 Many discrete and ICs need bipolar (dual or ± V) supplies. This can be easily accomplished with two three-terminal regulators, as illustrated in figure. Opposite-phase ac is provided by the transformer’s secondary and a grounded center tap. The single full-wave bridge converts these into positive and negative dc voltages (with respect to the grounded center tap). Filtering (with respect to ground) is provided by capacitors C1 and C2. The LM 340 provides regulation of the positive voltage, while the LM 320 regulates the negative voltage. It is very important to mention…

The output from any of the rectifier circuit is not purely dc but also has some ac components called ripples, along it. The ripples are maximum in the single phase half-wave rectifier and being reduced in the full-wave rectifier and being reduced further with the increase in the number of phases. Such supply is not useful for driving sophisticated electronic devices/circuits. Of course, for a circuit such as battery charger the pulsating nature of supply available from a rectifier is no great detriment as long as the dc level provided results in charging of battery. But for supply circuits to…

Three-Phase Half-Wave Rectifier: Figure illustrates a circuit for a 3-phase half-wave rectifier. The three diodes are connected to the three phases of a 3-phase transformer star-connected secondary. Neutral point N of the secondary forms the negative ter­minal for the load and is earthed, as illustrated in figure. Input and output waveforms are also shown in the figure. The effect of trans­former leakage reactance and re­sistance are neglected as it is the anode forward voltage drop. Each diode conducts during one-third of the cycle, as obvious from figure. When one diode conducts, the other two remain inactive be­cause then their cathodes…

In the bridge circuit four diodes are connected in the form of a Wheatstone bridge, two diametrically opposite junctions of the bridge are connected to the  secondary of a transformer and the other two are connected to the load. When the upper end of the transformer second­ary winding is positive, say during first half-cycles of the input supply, diodes D1 and D3 are forward biased and current flows through arm AB, enters the load at positive terminal, leaves the load at negative termi­nal, and returns back flowing through arm DC. Dur­ing this half of each input cycle, the diodes D2…

Centre-Tap Full-Wave Rectifier: In such a rectifier, the ac input is applied through a transformer, the anodes of the two diodes D1 and D2 (having similar characteristics) are connected to the opposite ends of the centre tapped secondary winding and two cathodes are connected to each other and are connected also through the load resistance RL and back to the centre of the transformer, as shown. centre-tap-full-wave-rectifier When the top of the transformer secondary winding is positive, say during the first half-cycle of the supply, the anode of diode D1 is positive w.r.t. cathode, and anode of diode D2 is…

When a single rectifier unit is placed in series with the load across an ac supply, it converts alternating voltage into uni-directional pulsating voltage, using one half cycles of the applied voltage, the other half cycles being suppressed because it conducts only in one direction. Unless there is an inductance or battery in the circuit, the current will be zero, therefore, for half the time. This is called half-wave rectification. As already discussed, diode is an electronic device consisting of two elements known as cathode and anode. Since in a diode electrons can flow in one direction only i.e. from…

General Introduction to DC power supplies: The electrical power is almost exclusively generated, transmitted and distributed in the form of ac because of economical consideration but for operation of most of the electronic devices and circuits, dc supply is required. Dry cells and batteries can be used for this purpose. No doubt, they have the advantages of being portable and ripple free but their voltages are low, they need frequent replacement and are expensive in comparison to conventional dc power supplies. Now a days, almost all electronic equipment include a circuit that converts ac supply into dc supply. The part…