Class C power amplifier. Class C power amplifier is a type of amplifier where the active element (transistor) conduct for less than one half cycle of the input signal. Less than one half cycle means the conduction angle is less than 180° and its typical value is 80° to 120°. The reduced conduction angle improves […]
Description. Here is a low noise preamplifier design for dynamic microphones. The circuit is based on the uA739 IC from Fairchild Semiconductors. uA739 is a dual audio operational amplifier with high gain and excellent stability. Out of the two opamps available in the IC, only one is used here. The audio signals from the microphone
In class AB power amplifiers, the biasing circuit is so adjusted that the operating point Q lies near the cut-off voltage. During a small portion of negative half cycle and for complete positive half cycle of the signal, the input circuit remains forward biased–and hence collector current flows. But during a small portion (less
Harmonic distortion in power amplifiers. Distortion is a serious problem faced in power amplifier design. In faithful amplification the output signal must be a scaled replica of the input signal and if there is any dissimilarity between the input and output waveform, then the output is said to be distorted. Unpleasant sound output coming from
Description. This is the circuit of a based audio preamplifier which has very low noise. One FET and one BJT are used in this circuit. The audio signal to be amplified is coupled to the base of FET Q1 using capacitor C1 and resistor R3.Base of transistor Q2 is coupled to the drain terminal of
Class B power amplifier. Class B amplifier is a type of power amplifier where the active device (transistor) conducts only for one half cycle of the input signal. That means the conduction angle is 180° for a Class B amplifier. Since the active device is switched off for half the input cycle, the active device
TRANSFORMER-COUPLED CLASS A POWER AMPLIFIER This is also sometimes referred to as single ended power amplifier. The term “single ended” (denoting only one transistor) is used to distinguish it from the push-pull amplifier using two transistors. In case of a direct-coupled class A power amplifier shown, the quiescent current flows through the collector resistive load
Class A power amplifier. Class A power amplifier is a type of power amplifier where the output transistor is ON full time and the output current flows for the entire cycle of the input wave form. Class A power amplifier is the simplest of all power amplifier configurations. They have high fidelity and are totally
Practical power amplifier. Audio power amplifier is an amplifier which produces amplification of power between the input and output. Theoretically every audio amplifier produces some amount of power amplification, but in practical scenario every audio amplifier cannot be called a power amplifier. It is the amount of power amplification that makes an amplifier power amplifier
An optocoupler (or an optoelectronic coupler) is basically an interface between two circuits which operate at (usually) different voltage levels. The key advantage of an optocoupler is the electrical isolation between the input and output circuits. With an optocoupler, the only contact between the input and the output is a beam of light. Because of
What is an LCD/Definition of Liquid Crystal Displays The liquid-crystal display has the distinct advantage of having a low power consumption than the LED. It is typically of the order of microwatts for the display in comparison to the some order of milliwatts for LEDs. Low power consumption requirement has made it compatible with MOS
A Light Dependent Resistor (LDR) is also called a photoresistor or a cadmium sulfide (CdS) cell. It is also called a photoconductor. It is basically a photocell that works on the principle of photoconductivity. The passive component is basically a resistor whose resistance value decreases when the intensity of light decreases. This optoelectronic device is
Introduction Optoelectronics is the branch of electronics that combines optics and electronics. The devices that deal with this technology is called optoelectronics devices. Optoeletronic devices can be divided into two – light sensitive devices and light generating devices. We have already discussed a good amount of optoelectronic devices in our site. You can get the
Description. This dual power supply is based on the L165 power operational amplifier from SGS-Thomson Micro electronics. The IC L165 can easily deliver up to 3.5A of current (internally limited). The IC is available in Pentawatt package and is very suitable for power supply applications like this. Here the L165 is wired as a voltage
Introduction To Power Amplifiers An amplifier system consists of signal pick-up transducer, followed by a small signal amplifier(s), a large signal amplifier and an output transducer. A transducer is used to convert one form of energy into another type. For example a microphone is used to convert acoustical energy into electrical energy. Conversely, a loudspeaker
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Description. This jet engine sound generator circuit is based on the sound generator IC HT2844P from Holtek Semiconductors. This particular IC can make four sounds namely low speed sound of jet engine, high speed sound of jet engine, missile sound and machine gun sound. Each of these sounds can be activated by connecting the pins
Description. Here is a very simple three transistor audio amplifier circuit that can deliver 250mW to a 8Ohm speaker. Complementary transistors BC337 and BC227 (Q3 and Q2) are used as the output pair. Transistor Q1 (BC 547) acts as the preamplifier.POT R5 can be used as a volume control. Capacitor C1 decouples the DC from
Description. This 13V/5A power supply is based on the famous LM338 IC from the ST Microelectronics. The IC has time dependent current limiting, thermal regulation and is available in 3 lead transistor package. The IC can easily supply well over 5A at an output voltage range between 1.2V and 30V. In this circuit the output
You might have read about a “Diode” in many of your text books or electronics magazines/websites. But you still don’t get the concept? Don’t worry! In this article, we explain in detail about a semiconductor diode and its properties. Well, a diode is nothing but a PN junction. We have crafted two excellent articles about
Description. The circuit is nothing but two LEDs (D1 and D2), whose status are controlled by the temperature of the surroundings. The famous IC LM35 is used as the temperature sensor here. Output of LM35 increases by 10mV per degree rise in temperature. Output of LM35 is connected to the non inverting input of the
What is a tunnel diode? Dr.Leo Esaki invented a tunnel diode, which is also known as “Esaki diode” on behalf of its inventor. Its a high conductivity two terminal P-N junction diode doped heavily about 1000 times greater than a conventional junction diode. Because of heavy doping depletion layer width is reduced to an extremely
Vacuum Diodes-Applications and Construction The simplest form of the electron tube for the production and control of free electrons is a Vacuum diode. Two electrodes are there for a vacuum diode known as anode and cathode. Cathode serves as an emitter of electrons where as anode serves as a collector of electrons. Cathode may be
Description. This is a very simple cable TV amplifier using two transistors. This amplifier circuit is most suitable for cable TV systems using 75 Ohm coaxial cables and works fine up to 150MHz. Transistor T1 performs the job of amplification. Up to 20dB gain can be expected from the circuit.T2 is wired as an emitter
Description. Here is the circuit diagram of a 10W audio amplifier using the popular TDA2003 IC from SGS Thomson. The IC can easily deliver 10W to a 4 Ohms load at 18V DC supply voltage. The IC can be also operated from 12V and that makes it applicable in car audio systems. The useful features
