Question

Solution problems: solve for the unknown quantity. 7. Calculate the frequency of a UJT relaxation oscillator when RE is 10K ohms and CE is 0.1uF. [Worth 5 points] 8. Suppose a square wave signal has a 65 percent duty cycle and an on-state voltage of 40 volts DC. What is the average DC voltage? [Worth 5 points] 9. If the full temperature range of an On-Off heating system is from 30 to 100 degrees and the differential gap is 5 degrees, what is the deadband? [Worth 5 points]

Answer 1

Given data: UJI Relaxation oscillator R_E = 10 k Ohm C_E = 0.1 mu F f = ? Frequency (f) = 1/T T = Rc ln [1/1-n] eta = intrinsic stand-off ratio eta = 0.65 (2N 2646 data sheet) T = 10 times 10^3 times 0.1 times 10^-6 ln [1/1-0.65] T = 1.049 ms Frequency (f) = 1/T = 1/1.049 ms (f) = 952.54 Hz \r\n Duty cycle percent = 65 % ON-state Voltage (V) = 40 V Average DC voltage = On state Duty cycle (V_dc) = 40 times 65/100 V_dc = 26 V Given data: Different gap = 100-30 = 70 degree Differential gap = 50 degree Dead band (% Dif Gap) = Differential Gap/Total Range Dead Band (% Diff Gap = 95/70 Dead band = 7.14 %