AC Voltage Expression and understanding

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Discussion Overview

The discussion revolves around the expression of AC voltage given as 240 cos(2765t - 45°) and the calculations related to its various forms: Peak Voltage, RMS Voltage, Average Voltage, and Peak-to-Peak Voltage. Participants are attempting to verify their calculations and seek clarification on the correct equations to use.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents their calculations for Peak Voltage (240v), RMS Voltage (170v), Average Voltage (0v), and Peak-to-Peak Voltage (480v), expressing uncertainty about the equations used.
  • Another participant agrees that the calculations appear correct, but does not provide further clarification or corrections.
  • A third participant mentions reworking their calculations multiple times due to uncertainty about their correctness.
  • There is a hijacked discussion about ham radio and Morse Code, which diverges from the original topic of AC voltage.

Areas of Agreement / Disagreement

There is no clear consensus on the correctness of the calculations, as one participant agrees with the results while another expresses doubt. The discussion remains unresolved regarding the proper equations and methods to use.

Contextual Notes

Participants have not provided detailed justifications for their calculations, and there may be missing assumptions regarding the definitions of RMS and average voltage in the context of AC signals.

nightTerror
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1. The problem statement.

AC voltage is expressed as 240 cos(2765t - 45°).
Im trying to find the:

Peak Voltage:
RMS Voltage:
Average Voltage:
Peak-to-Peak Voltage:

The Attempt at a Solution



Peak Voltage: 240v
RMS Voltage: 170v
Average Voltage: 0v
Peak-to-Peak Voltage: 480v

I've worked on this but i feel like I am using the wrong equations to find the answer. such as Peak to Peak and RMS.

Any ideas?
Thanks for your help
 
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nightTerror said:
1. The problem statement.

AC voltage is expressed as 240 cos(2765t - 45°).
Im trying to find the:

Peak Voltage:
RMS Voltage:
Average Voltage:
Peak-to-Peak Voltage:

The Attempt at a Solution



Peak Voltage: 240v
RMS Voltage: 170v
Average Voltage: 0v
Peak-to-Peak Voltage: 480v

I've worked on this but i feel like I am using the wrong equations to find the answer. such as Peak to Peak and RMS.

Any ideas?
Thanks for your help

Answers so far look correct to me.
 
Thanks, I've reworked it about 3 times because I thought I was doing it wrong.
 
berkeman said:
Signature:
"Newark, CA, USA, HAM Radio EC (Emergency Coordinator), 2m, 70cm, 1.2GHz
Morse Code is no longer required for your HAM license in the USA!"

I had a ham license from 1953 to about 1973 and used to love CW. Apparently they have lowered the exam standards there like everything else. Are the CW bands still alive and well? That would seem like the death knell to me...
 
LCKurtz said:
I had a ham license from 1953 to about 1973 and used to love CW. Apparently they have lowered the exam standards there like everything else. Are the CW bands still alive and well? That would seem like the death knell to me...

<hijack>

The CW bands are good now -- as you know they cycle with sunspot activity, and we are near the peak of the 11 year cycle right now, so skip off the ionosphere is good right now. We just had Field Day recently (did you participate in those when you were active?), and our local club had a near record number of contacts. Great stuff.

The dropping of the CW (Morse Code for the PF readers who are non-HAMs) requirement for getting HAM licenses was done by the FCC to bolster the ranks of the emergency response HAM operators, and has had very little effect on the HAM operators who enjoy long-distance CW contacts and contesting. Actually, I know several new HAMs who are learning CW after getting their license, because they have a general interest in all communications, and learning CW expands the modes that they can operate in.

As an ARES EC for my city, I get e-mails each month that list the new HAM licenses that have been issued. The increase is dramatic since the FCC eliminated the CW requirement, and I am quite busy training up new HAM operators in how to be effective communicators in disaster situations. IMO, this was a great move by the FCC, and it has helped us locally in our disaster preparations significantly. (I basically live on top of the Hayward Fault, which is due to slip very soon...)

</hijack> :biggrin:
 

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