Alternating Current (AC)
Alternating current describes the flow of charge that changes direction periodically. As a result, the voltage level also reverses along with the current. AC is used to deliver power to houses, office buildings, etc.
Generating AC
AC can be produced using a device called an alternator. This device is a special type of electrical generator designed to produce alternating current.
A loop of wire is spun inside of a magnetic field, which induces a current along the wire. The rotation of the wire can come from any number of means: a wind turbine, a steam turbine, flowing water, and so on. Because the wire spins and enters a different magnetic polarity periodically, the voltage and current alternates on the wire
Direct Current (DC)
Direct current is a bit easier to understand than alternating current. Rather than oscillating back and forth, DC provides a constant voltage or current.
Generating DC
DC can be generated in a number of ways:
How are the ions arranged in an AC vs. a DC plasma?
Single phase square to supply an ac load from dc power supply with source voltage VS = 20 volts wave full bridge inverter will be designed. The load resistance is R = 24 ohms and L = 240 milliHenry. Exit the frequency of its voltage will be 25 Hz. With the minimum value of the load current at t = 12ms and t = 30ms Calculate the values.
QUESTION 1 While connecting a DC system to the AC system using an inverter, the DC voltage is lower than the voltage at the AC system O True O False
Question 2 Why use dc motors when ac power is delivered on the line? a. dc motors are grandfathered in from a time when dc power was delivered to the customer. b. dc mototrs maintain a higher efficiency while having a wide torque-speed charateristic. c. ac motors are more complicated and challenging to make than dc motors. d. None of the above.
Example 13.4: For the figure below, a) Draw AC and DC load lines for both transistors. b) Calculate the overall voltage gain Avs o/vs c) Find s(max) which produces maximum undistorted output voltage. 20V Q1 Q2 hFE=htp= 100 100k2 Rc 1k R VBE 0.6V R2>100k Q2 R. Cc Q1 Co 1kn o Vo R1 10k RE2 1k RL1K2 RE1 1kn CE Figure 13.6: An AC-coupled two-stage BJT amplifier for Example 13.4. Example 13.4: For the figure below, a) Draw AC...
In an AC to DC rectifier circuit, the output DC signal of the rectified wave was measured to be VDC= (9.1±0.6)V and its ripple voltage was measured to be Vripple=(0.14±0.03) mV. What is the uncertainty on the quality factor of the rectifier? (Report your final value to 2 sig figs)
Why DC mean voltage is zero for AC signals
bridge oad DC DC Vload DC For a single-phase DC-AC inverter with an RL load at the output. It is switching using the bipolar SPWM method with the desired fundamental frequency of 400 Hz and the switching frequency of 20.4 kHz. Here the modulation index is 0.6, input DC is 200 V, load R-5 Ω and L 2 mH a. What's the RMS value of the fundamental component of the output voltage across RL? b. What's the RMS value of...
Variable frequency electronic generation of sinusoids first requires the grid AC to be rectified into DC. Next the DC is converted to high f AC by an inverter circuit. The entire process is at 95% efficiency. Below you are required to refresh your understanding of AC to DC rectifiers. Diode rectifiers are non-linear loads so grid power factor and harmonic generation are again a consideration. The total power factor is composed of two parts: the distortion power factor due to...
A DC and AC voltmeter are used to measure the output voltage of a filter circuit connected to full wave rectifier circuit operating at 60Hz, supplying load of 5hp DC Motor (1hp=0.75kW). The readings of the two voltmeters are 250V and 2.0V respectively. Calculate a) The ripple factor of the filter. b) The value of filter capacitor.