Figure 1 shows three basic waveforms that are represented by the time domain concept. The three waveforms shown are sine wave, square wave, and sawtooth wave. Although the three waveforms are different, they all have the same period of frequency. By using various electronic circuits, these waveforms can be changed from one shape to another. …
An oscillator is a circuit that generates a repetitive AC signal. The frequency of the AC signal may vary from a few hertz to many millions of hertz. The oscillator is an alternative to the mechanical generator used to produce electrical power. The advantages of the oscillator are the absence of moving parts and the …
Operational amplifiers are usually called op-amps. An op-amp is a very high-gain amplifier used to amplify both AC and DC signals. Typically, op-amps have an output gain in the range of 20,000 to 1,000,000 times the input. Figure 1 shows the schematic symbol used for op-amps. The negative (-) input is called the inverting input …
Audio amplifiers amplify AC signals in the frequency range of approximately 20 to 20,000 hertz. They may amplify the whole audio range or only a small portion of it. Audio amplifiers are divided into two categories: voltage amplifiers and power amplifiers. Voltage amplifiers are primarily used to produce a high voltage gain. Power amplifiers are …
Direct-coupled or DC amplifiers are used for high gain at low frequencies or for amplification of a direct-current signal. The DC amplifier is also used to eliminate frequency loss through a coupling network. Applications of the DC amplifier include computers, measuring and test instruments, and industrial control equipment. A simple DC amplifier is shown in …
To obtain greater amplification, transistor amplifiers may be connected together. However, to prevent one amplifier’s bias voltage from affecting the operation of the second amplifier, a coupling technique must be used. Amplifier Coupling Methods The coupling method used must not disrupt the operation of either circuit. Coupling methods used include resistance-capacitance coupling, impedance coupling, transformer …
In order for a transistor to provide amplification, it must be able to accept an input signal and produce an output signal that is greater than the input. The input signal controls current flow in the transistor. This, in turn, controls the voltage through the load. The transistor circuit is designed to take voltage from …
When higher DC voltages are required, a step-up transformer is used. However, higher DC voltages can be produced without a step-up transformer. Circuits that are capable of producing higher DC voltages without the benefit of a transformer are called voltage multipliers. Two voltage multipliers are the voltage doubler and the voltage tripler. Half Wave Voltage …
Two factors can cause the output voltage of a power supply to vary. First, the input voltage to the power supply can vary, resulting in increases and decreases in the output voltage. Second, the load resistance can vary, resulting in a change in current demand. Many circuits are designed to operate at a certain voltage. …
Light is electromagnetic radiation that is visible to the human eye. The frequency range of light is: Light waves at the upper end of the frequency range have more energy than light waves at the lower end. Light Sensitive Devices Semiconductor devices that interact with light can be classified as: light-detection devices, light-conversion devices, or …
