Analog vs. Digital Sine - Short #179

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 21 November 2023

⏱️ 8 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

In this short podcast, Bryan breaks down the differences between analog and digital sine waves.

Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read them on an oscilloscope (in the US, we see 60 peak-and-valley cycles per second because the frequency is 60 hertz).

Variable frequency drives (VFDs) and ECMs work with digital outputs instead. The alternating current (AC) input is flattened out and then replicated as a direct current (DC) digital output that mimics an analog sine wave using technologies like pulse-width modulation (PWM). Digital outputs appear as a series of steps on an oscilloscope, but PWM doesn't output different "steps" of voltage. PWM just changes the length and frequency according to the duty cycle (percentage of the time energized or unenergized). Digital scrolls turn on and off very often, and the time they spend "on" is the duty cycle, which determines how it stages up and down.

While ECM motor modules usually won't work with regular motors, VFDs can run with typical motors and modify sine waves. These sine waves don't have a smooth curve, but the digital waves can be smoothed out while voltage and current are modified. If VFD-driven motors aren't designed or shaft-grounded properly, electrical discharge machining (EDM) can happen with high-frequency voltage spikes, which can damage the shaft and bearings.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Transcript

Click on a timestamp to play from that location

0:00.0	Greetings and salutations. This is the H.E.C. School Podcast and this is a short episode and today
0:09.9	we're going to talk about different types of sign waves,
0:12.8	analog and digital, and really just try
0:14.8	to introduce you to the ideas of analog and digital
0:17.2	and a few other words that maybe you don't know.
0:19.9	Lots of acronyms, lots of initials for things.
0:22.3	So if you're into that kind of thing, stick around. But before we do that, let's hear from our great sponsors.
0:27.0	HVAC contractors and techs, the Censi Touch 2 smart thermostat now has even more features to offer your customers,
0:35.2	including balanced point and auxiliary lockout temperatures and expanded
0:39.0	Wi-Fi compatibility.
0:41.0	Learn more by going to HVACR School.com
0:43.4	slash touch too.
0:46.0	Carrier and carrier.com.
0:48.6	Carrier has been a long-term sponsor of the podcast.
0:51.2	They've made it possible very early on for us to do what we do and
0:54.8	they are the products that we sell day in a day out. Everything from single stage
0:58.7	equipment all the way up to the green speed extreme, one of the most efficient products on the market today.
1:05.7	Find out more about what carrier has to offer and about becoming a carrier dealer by going
1:10.3	to carrier.com.
1:12.9	Refrigeration Technologies and specifically Viper Wipes,
1:17.2	the all-purpose wipe that is really amazing
1:20.9	what it can cut through.
	...

Please login to see the full transcript.

Previous episode | Next episode

Disclaimer: The podcast and artwork embedded on this page are from Bryan Orr, and are the property of its owner and not affiliated with or endorsed by Tapesearch.

Generated transcripts are the property of Bryan Orr and are distributed freely under the Fair Use doctrine. Transcripts generated by Tapesearch are not guaranteed to be accurate.