I am now working on a question that says, 5. A microphone has an output power of 45 dBm, the output power in Watts is; A. 5.6 mW B. 31.6 μW C. 5.6 nW D. 31.6 nW E. None of the above i found the formula to convert dBm to watts which is P(Watts)= 10^(dB/10)/1000 i dont actually know exactly what is the formula saying apart from the divide by 1000 part because 1watt = 1000mV 10^(-45/10)/1000= 0.0000000316227766 Watts but then i multiplied the Ans by various submulitples to get me an answer that are in the options. i did 0.0000000316227766 x 10^9(nanowatts)= 31.6nW is this the correct way of getting the answer?
dBm is dB with respect to a reference power of 1 milliwatt = .001 Watt. Your answer is correct. I always get the right answer by writing the definition and doing the algebra. Code ( (Unknown Language)): -45 dBm = 10*log(Po/Pref), where Pref = 1 mW -45 / 10 = log(Po /.001) -4.5 = log(Po/.001) Po = 10^(-4.5) * .001 Po = 3.162e-8 For me is is just easier to start with the definition and do the algebra. Your mileage may vary.
I've dragged my trees out of the forest dozens of times with the, "back to basics" approach recommended by Papabravo. I must agree with his method.