Chapter 16, POWER SUPPLIES Video Solutions, Operational Amplifiers and Linear Integrated Circuits

01:05

Problem 1

A transformer is rated at 115 to $28 \mathrm{Vrms}$ at $1 \mathrm{~A}$. What is the peak secondary voltage?

Narayan Hari

Numerade Educator

07:17

Problem 2

A $115 / 28 \mathrm{~V}$ transformer is used in Fig. 16-4(a). Find $V_{\mathrm{dc}}$ at no load.

Nikhil Tiwari

Numerade Educator

01:59

Problem 3

As de load current increases, what happens to (a) dc load voltage; (b) ac ripple voltage?

Vishal Gupta

Numerade Educator

03:24

Problem 4

In Fig. 16-4, the transformer rating is 115 to $28 \mathrm{~V}$ at $1 \mathrm{~A}$. What is $V_{\mathrm{dc}}$ at a full-load current of $I_L=0.5 \mathrm{~A}$ ?

Zulfiqar Ali

Numerade Educator

04:11

Dc measurements of a power supply give $V_{\mathrm{dc} \mathrm{NL}}=17.8 \mathrm{~V}$ and $V_{\mathrm{dc}} \mathrm{FL}=13.8 \mathrm{~V}$ at $I_{L \mathrm{FL}}=$ $0.5 \mathrm{~A}$. Calculate: (a) $R_o$; (b) percent regulation.

Ben Nicholson

Numerade Educator

00:55

Problem 6

What voltage readings would be obtained with an ac voltmeter for peak-to-peak ripple voltages of (a) I $\mathrm{V}$; (b) $3 \mathrm{~V}$ ?

Hunza Gilgit

Numerade Educator

01:01

Problem 7

The de full-load voltage of a power supply is $28 \mathrm{~V}$ and the peak-to-peak ripple voltage is $6 \mathrm{~V}$. Find the minimum instantaneous load voltage.

Sheh Lit Chang

University of Washington

01:37

Problem 8

A $110 \mathrm{~V} / 28 \mathrm{~V}$ CT transformer is installed in Fig. 16-8. What no-load dc voltage would be measured (a) between terminals 1 and 2 ; (b) from 1 to CT; (c) from 2 to CT?

Mrinal Rana

Numerade Educator

01:14

Problem 9

Find the percent ripple in Example $16-7$ if $C$ is changed to $2000 \mu \mathrm{F}$.

Ahmad Reda

Numerade Educator

01:40

Problem 10

Design an FWB unregulated power supply to output $+15 \mathrm{~V}$ at $1 \mathrm{~A}$, with less than $5 \%$ ripple. Assume that $R_o=8 \Omega$. Choose the transformer from available ratings of $115 / 12 \mathrm{~V}$, $115 / 18 \mathrm{~V}$, and $115 / 24 \mathrm{~V}$-all at $2 \mathrm{~A}$. Available capacitors are $500 \mu \mathrm{F}$ and $1000 \mu \mathrm{F}$ at WVDC $=50 \mathrm{~V}$.

Narayan Hari

Numerade Educator

02:40

Problem 11

Given 115/25.2 V at a 3-A transformer and $C=1000 \mu \mathrm{F}$ in an FWB rectifier. Assume $R_o=6 \Omega$ and $l_{L \mathrm{FL}}=1 \mathrm{~A}$. Calculate (a) $V_{\mathrm{dc} \mathrm{NL}} ;$ (b) $V_{\mathrm{dc} \mathrm{FL}} ;$ (c) percent regulation; (d) $\Delta V_o$; (e) ripple; (f) $V_{L \text { min }}$.

Zhuxi Luo

Numerade Educator

01:19

Problem 12

An unregulated power supply has $V_{\mathrm{dc}} \mathrm{NL}=18 \mathrm{~V}, V_{\mathrm{dc}} \mathrm{FL}=10 \mathrm{~V}$ at $1 \mathrm{~A}, \Delta V_o=5 \mathrm{~V}$, and $C=1000 \mu \mathrm{F}$. Calculate $\Delta V_o$ if you (a) double $C$ to $2000 \mu \mathrm{F}$, or (b) reduce $I$ to $0.5 \mathrm{~A}$, or (c) both reduce $I$ to $0.5 \mathrm{~A}$ and double $C$ to $2000 \mu \mathrm{F}$.

Khoobchandra Agrawal

Numerade Educator

07:16

Problem 13

An ac voltmeter indicates a value of $1.71 \mathrm{~V} r \mathrm{~ms}$ across the FWB supply, and a dc voltmeter indicates $12 \mathrm{~V}$ dc. Draw the expected value of $V_L$ that would be seen on a dc-coupled oscilloscope for a time interval of $16.7 \mathrm{~ms}$ (see Fig. 16-7).

João Gabriel Alencar Caribé

Numerade Educator

01:04

Problem 14

If $I_L$ measures I A in Problem 16-13, find (a) the value of $C$; (b) the value of $R_L$.

Goutam Chand

Numerade Educator

View

Problem 15

You need a regulated output voltage of $24.0 \mathrm{~V}$. If $R_1=240 \Omega$ in Fig. 16-13(a), find the required value of $R_2$.

Lainey Roebuck

Numerade Educator

00:43

Problem 16

Assume that the regulator of Problem 16-15 delivers a load current of $1.0 \mathrm{~A}$. If its average dc input voltage is $30 \mathrm{~V}$, show that the regulator must dissipate $6 \mathrm{~W}$.

Averell Hause

Carnegie Mellon University

07:07

Problem 17

Find $V_o$ if $R_2$ is short-circuited in (a) Fig. 16-13(a); (b) Fig. 16-13(b).

Thomas Thompson

Numerade Educator

00:49

Problem 18

Adjustable resistor $R_2=0$ to $2500 \Omega$ in Fig. 16-13(a). Find the upper and lower limits of $V_o$ as $R_2$ is adjusted from $2500 \Omega$ to $0 \Omega$.

Ze-Han Lee

Numerade Educator

02:16

Problem 19

Suppose that a $1200-\Omega$ low-stop resistor, and a $2500-\Omega$ pot are connected in series in place of the single resistor $R_2$ in Fig. 16-13(a). Find the upper and lower limits of $V_o$ as the pot is adjusted from $2500 \Omega$ to $0 \Omega$.