can you help on these

[searley]

can`t get formulas for these ?

1.when a semi conductor diode is connected across an ac supply having a peak value of 5v,the peak inverse voltage across the diode is ?

2.a circuit has a resistance of 20ohms and an inductive reactance of 15ohms when connected to an ac supply.the impedance of the circuit is ?

thanks for the help chaps.

answer 1, 7.07 2, 25.0ohms

 

[M107]

I think question one is along the lines of the PIV should be 1.4 times greater than the supply voltage rms..............that is a dim memory but I do remember something along that line & cant be arsed to dig out & dust off the old notes from college.

Question 2

Z=square root of R + XL

Z = impeadance

R = resistance

XL = inductive reactance

Z= sqrt of (20x20) + (15x15)

Z= sqrt of (400 + 225)

Z= sqrt of 625

Z= 25

Something like that.............I hope

 

[Andy™]

for Q 1 - RMS is .7071 of peak voltage - so if RMS is 5V, peak voltage is RMS / .7071 = 7.07V

for Q2 - M107 has it right