11-23 A certain thermocouple provides outputs in the vicinity of 0.05 mV/°C with a constant k equal to 5 x 10-5 mV/°C and 7₁ = 80°C; the cold junction is kept in ice. Compute the resultant electromotive force. 11-24 Using the same thermocouple as in Problem 11-23. find the temper- ature of the hot junction if the output voltage is 5 mV. (Hint: Use an approximate equation by deleting the second term.) 11-25 The circuit of Fig. 11-18 is being used for temperature measurement. A "15-k" thermistor (Fig. 11-16) is used. The meter is a 100-μA ammeter with a resistance of 1800, R is set to 8 KQ, and the supply voltage V, is 10 V. What will the meter read at 100°F and at 400°F? 11-26 In Problem 11-25 a 150-mV voltage is applied to the thermistor in series with a relay. What temperature causes the relay to be ener- gized? (The energizing current is 1 mA.) 11-27 We are given the circuit of Fig. 11-23 using a 10-V supply voltage. A current of 5 mA flows when the cell is illuminated with about 400 lm/m², and deenergized when the cell is dark. Find (a) The required series resistance R₁. (b) The level of dark current. 11-28 The input voltage of Problem 11-27 is decreased to 10 V. Find (a) The current flowing at 400 lm/m². (b) The level of dark current. 11-29 Given the photodiode circuit (Fig. 11-25) and photodiode character- istic curve with the load line (Fig. 11-24). at an illumination of 5000 lm/m², find (a) The diode current. (b) The IR drop across R₁. (c) The diode drop. 11-30 We are given the same photodiode and characteristic curve of Problem 11-29. The photodiode is forward-biased at an illumination of 20,000 Im/m². Find. (a) The diode current. (b) The IR drop across R₁. (c) The diode drop. (d) The resistance of the photodiode. 11-31 Given the circuit and characteristic curve of Fig. 11-28, at an illumination level of 300 W/m², find

A 15-F AC capacitor is connected in series with a 50 resistor. The capacitor has a voltage rating of 600 WVDC. The capacitor and resistor are connected to a 480-V, 60-Hz circuit. Is the voltage rating of the capacitor sufficient for this connection?

Find the Current in the Circuit in Miliampares

C'uk Converter Design A C'uk converter has an input of 12 V and is to have an output of - 24 V supplying a 60 W load. Select the duty ratio, the switching frequency, the inductor sizes such that the change in inductor currents is no more than 12 percent of the average inductor current, the output ripple voltage is no more than 1.5 percent, and the ripple voltage across C1 is no more than 3 percent.