We talked about lots of good stuff last night at the Office Hours webinar. I started off with a brief presentation on Neutral and Ground in AC circuits, explaining how they are different and each serves different purposes in AC circuits.
Then we applied what we learned about power supplies in that presentation to decipher some crappy instructions in a service bulletin for a Whirlpool inverter microwave where we had to figure out how to test the digital data input to the inverter.
We then spring boarded off that to talk about digital data communications in appliances. Even though the example we used was a Samsung dishwasher, the principles we discussed are common to ALL appliances, regardless of brand or model.
While we were talking about digital data communications, it seemed like a good flow to get into a discussion about "loading down" in DC power supplies and the troubleshooting technique we would use to test for this. We also talked about why loading down is not an issue affecting AC loads.
But AC loads and switches have their own special way of failing that we as techs need to be aware of: failing under load. So we talked about why we don't trust ohms testing for AC loads and switches.
Finally, we talked about how a high resistance connection (less than 5 ohms!) at a thermostat in an electric dryer can cause long dry times by robbing wattage from the heating element. We worked through a simple Ohm's Law calculation to show how this happens. This little exercise also illustrated the value of having the Ohm's Law pie chart readily accessible in the photo album of your phone so you don't have to rely on memory because it plays tricks on you!
Professional Appliantologist members can watch the webinar recording here.
Master Samurai Tech students can watch it here.