China
Africa
Explore chapters and articles related to this topic
Stability Analysis
Published in Amitava Sil, Saikat Maity, Industrial Power Systems, 2022
The disturbances can be small such as small load changes or random load changes occurring under normal load condition and large such as loss of generator, a fault or loss of line. Small disturbances are those for which the equations that describe the dynamics of the power system may be linearized for the purpose of analysis. Large disturbances are which for those the equations that describe the dynamics of the power system cannot be linearized for the purpose of analysis. Different types of stability are (i) Steady State Stability – studies are restricted to small and gradual changes in the system operating conditions. A power system is steady state stable for a particular steady state operating condition if, following any small disturbance, it reaches a steady state operating condition which is identical/close to the pre-disturbance operating condition. It is often termed as small signal stability (ii) Dynamic Stability – The ability of a power system to maintain stability under continuous small disturbances is investigated under the name of Dynamic Stability or small signal stability; (iii) Transient Stability – A power system is transiently stable for a particular steady state operating condition and for a particular disturbance, if following the major disturbance, it reaches an acceptable steady state operating condition. It is often termed as large signal stability. Transient Stability limit is lower than the steady state stability limit.
Electronic Circuits in Action
Published in Trevor Linsley, Electronic Servicing and Repairs, 2014
When an amplifier is used to amplify the input voltage or current in such a way that the output is an enlarged copy of the input and is not distorted, it is said to be a small signal amplifier. When an amplifier is used to amplify the power of an input signal it is said to be a power amplifier.Figure 5.26 shows the circuit diagram of an audio frequency amplifier. The left-hand side of the circuit, the op amp, is a small signal voltage amplifier which is used to amplify a small signal from, for example, the ear piece jack plug of a tape recorder. The right-hand side of the circuit is the power amplifier which is required to drive the speaker. This is made from a pair of complementary power transistors, one is an n-p-n and the other a p-n-p transistor which have beenmatched so that they have the same gain and other properties. When the voltage on the top transistor is positive the voltage on the bottom transistor is negative and vice versa. The amplification of each half of the voltage waveform is, therefore, shared between the two transistors. A circuit which is constructed in this way is known as a push-pull amplifier. The additional power required to drive the speaker in this circuit comes from the 9 V batteries.
Electronic Communications
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
The audio-frequency (AF) amplifier of a CW receiver is responsible for increasing the level of the developed sound signal. The type and amount of signal amplification varies widely among different receivers. Typically, a small-signal amplifier and a power amplifier are used. The small-signal amplifier responds as a voltage amplifier. This amplifier is designed to increase the signal voltage to a level that will drive the power amplifier. Power amplification is needed to drive the speaker. The power output of a communication receiver rarely ever exceeds 5 W. A number of the AF amplifier circuits in Chapter 14 could be used in a CW receiver.
A Holistic Experimental Static Bias Point Identification Method for Low Power Wireless RF Amplifier
Published in IETE Journal of Research, 2022
Saroj K. Patro, Rabindra K. Mishra, Ajit K. Panda
The small signal swept frequency simulated performance of the amplifier is shown in Figure 4. As observed, the small signal gain of the amplifier is approximately 18.25 dB in the mid-band with an overall flatness of better than 0.7 dB. Also, the amplifier obtained good input and output return loss. The large signal swept power simulated performance is shown in Figure 5 which depicts three parameters such as the power gain, 1 dB gain compression Power (P1 dB) and 3 dB gain compression Power (P3dB) levels. As observed here, the P1dB for the amplifier is about +37.03 dBm and P3dB is about +38.13 dBm at 1960 MHz. The P1dB and the P3dB are the 1-dB and 3-dB gain compression points of the device and these simulated values are in accordance with the device datasheet predicted performance. These gain data clearly depict the linear and non-linear region of the amplifier before the compression point is reached.