- #1
phiby
- 74
- 0
Since the deci in decibels means 10, why is decibels of Magnitude in the Bode plot calculated as 20log instead of 10log?
Click For Summary
The Bode plot utilizes 20log for decibels of magnitude because power is proportional to the square of amplitude. Since the Bode plot focuses on amplitude rather than power, the logarithmic relationship necessitates an extra factor of 2. This is expressed mathematically as 10log(P) transforming into 20log(A) due to the relationship P ∝ A². Therefore, the use of 20log accurately reflects the amplitude's contribution to the power gain in decibels. Understanding this distinction is crucial for interpreting Bode plots correctly.
- #2
I like Serena
Science Advisor
Homework Helper
MHB
- 16,335
- 258
Hi phiby! 
The Bode plot shows the power gain in dB.
Power is correlated to the square of the amplitude.
Since amplitude is used as input, you get an extra factor 2.
In formula form:
P \propto A^2
10 \cdot \log {P \over P_0} = 10 \cdot \log {A^2 \over A_0^2} = 20 \cdot \log {A \over A_0}
The Bode plot shows the power gain in dB.
Power is correlated to the square of the amplitude.
Since amplitude is used as input, you get an extra factor 2.
In formula form:
P \propto A^2
10 \cdot \log {P \over P_0} = 10 \cdot \log {A^2 \over A_0^2} = 20 \cdot \log {A \over A_0}
I grabbed an under cabinet LED light today at a big box store. Nothing special. 18 inches in length and made to plug several lights together. Here is a pic of the power cord:
The drawing on the box led me to believe that it would accept a standard IEC cord which surprised me. But it's a variation of it. I didn't try it, but I would assume you could plug a standard IEC cord into this and have a double male cord AKA suicide cord. And to boot, it's likely going to reverse the hot and...
Similar threads
- · Replies 13 ·
- · Replies 12 ·
- · Replies 9 ·
- · Replies 6 ·
- · Replies 8 ·
- · Replies 3 ·
- · Replies 4 ·