![]() Then Amplifier Classes is the term used to differentiate between the different amplifier types.Īmplifier Classes represent the amount of the output signal which varies within the amplifier circuit over one cycle of operation when excited by a sinusoidal input signal. One method used to distinguish the electrical characteristics of different types of amplifiers is by “class”, and as such amplifiers are classified according to their circuit configuration and method of operation. A typical loudspeaker has an impedance of between 4Ω and 8Ω, thus a power amplifier must be able to supply the high peak currents required to drive the low impedance speaker. Generally, large signal or power amplifiers are used in the output stages of audio amplifier systems to drive a loudspeaker load. The main operating characteristics of an ideal amplifier are linearity, signal gain, efficiency and power output but in real world amplifiers there is always a trade off between these different characteristics. There is a clear distinction made between amplifier classes as too the way their output stages are configured and operate. Lyzhin R, Radiokonstruktor 2003, November.Not all amplifier designs are the same. The choke has 50 turns of 32.38 AWG enameled wire. The RF choke L2 is wound on a ferrite toroidal core of 7 mm in diameter. This design uses the same ferrite rod antenna as the previous one. ![]() Note, the diode D1 is connected into bias circuit of the transistor T2, such configuration increases the sensitivity of the detector because of a DC current passing through the diode D1. The amplified RF voltage goes from the first stage through the capacitor C3 to the envelope detector with the diode D1, and the audio signal goes from the envelope detector to the audio amplifier based on the transistor T2. The RF choke L2 is connected in collector circuit of transistor T1. The resonant tank connected to the RF amplifier (transistor T1) in the same way as it connected in the previous circuit (fig. The output of this receiver is connected to stereo headphones with the summary impedance not less than 32 Ω, so the quality of the sound is better. It works with the lower power supply of 1.5 Volts. The second circuit of the radio receiver is shown in figure 2. The adjustment of the circuit is quite simple - match the value of R1 to get the sound in headphones as loud as possible. The coil L1 has 90 turns of 26.32 AWG enameled copper wire, tapped at the 10th turn. The coil L1 is wound in one layer on a ferrite rod of 8 mm in diameter (permeability μ e=400), with the length of about 70 mm. This receiver works with headphones, the summary resistance of LS1 must be not less than 1500 Ω. This stage not only amplifies the signal, but also demodulates the AM radio signals. The amplified signal voltage from the collector T1 goes to the base of the transistor T2. The transistor T1 amplifies the RF signal. This coil and the variable capacitor C1 are resonant tank elements of the ferrite rod antenna that receive RF signals of radio stations. The bias voltage at the base of the transistor T1 is set by the resistor R1, the bias current goes through the coil L1, its resistance for DC is almost zero. ![]() Both transistor stages are connected without an inter-stage coupling capacitor. The circuit diagram shown in figure 1 is quite unusual. Here are two simple circuits of radio receivers for Middle Wave band, working with headphones. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |