Power Management, Chapter 8: Power Management ICs | Circuit Breaker Parts

I do not claim infallibility. I invite criticism of my designs. But I insist on that criticism be based on my work rather than be mere FUD.

Would that we solved with two opto’s per button, one to read and one to press ? Ignoring the LED feature entirely. Because you cannot assign a pin to be both input and output.

The microwave I recently tore apart had a hefty resistor connecting the capacitor to ground, to quickly drain it of power when the magnetron itself wasn’t energized. (The capacitor itself had a label saying there should be a resistor bridging the cap’s contacts for the same purpose.)

Tilt / swivel LCD. At the rear, the 3-inch LCD dominates much of the available real-estate, and its tilt/swivel mechanism — appearing for the first time in an Alpha camera — can be clearly seen. The display tilts down 180 degrees and then swivels 270 degrees, allowing it to face any direction except to the front right (handgrip) quadrant. The design not only allows easy framing of high- and low-angle shots, but also allows subjects in front of the lens to see themselves — but only when somebody’s available to hold the camera. Since the display tilts downwards, it will be blocked from view when mounted on a tripod, and can’t be extended beyond the 90-degree position with the camera placed on a flat surface, so the only way to use it for self-portraits is to hold the camera at arm’s length. It can also be difficult to deploy and use with the camera mounted on a tripod.

You likely encountered a shared neutral between more than one circuit. You have to switch off the breakers for all the circuits that share the neutral.

This plate is too likely to touch the user. It’s sensible to have a certain fear of mains voltages, makes you pay attention when you’re working with it. The DC power suggested would come from the printer’s existing PSU, pay a little bit extra for a few more amps, the overall wattage isn’t high. Much less than I presume you’d use in industry. Thanks to power-hungry graphics cards, high-power PC PSUs are cheap.

You don’t need a big contactor to switch 1A at 120v, you can get little “ice cube” relays that switch up to 10A at 120V and they have a plug-in base so easy to change out when they inevitably fail. Most of them, in new perfect condition, make barely any sound. Nothing compared to the noise of fans and stepper motors. The only issue I can see is running AC mains voltage through wiring that is going in parallel with low voltage. Would need to use thick jacketed, shielded cable to prevent too much EMI. Maybe it’d be better suited using a separate transformer just for the heated bed, rectified/regulated but still a higher voltage for better efficiency. Speaking just from my experience as an electrician and hobbyist level electronics/3d printing experience.

Actually most power panels I have worked on alternate phases as you go down the opposite rows, not one phase on each side, 240 breakers take up 2 breaker spaces on one side of the panel using alternate legs.

In reviewing my experience with the Sony A55 and A33, it’s interesting to find so many of my notes and so much of my attention directed to the viewfinder display. Were I not already so familiar with Sony’s multi-shot exposure technology, the camera’s multi-shot features would doubtless have commanded more of my attention, as they’re worthy features indeed. That said, though, the viewfinder turned out to be absolutely integral to my experience with the camera.

After checking to make sure the outlets are wired correctly, a 220v light bulb with light up across the two hots if they are opposite phase and not if they are the same phase.

You may be confusing voltage drop ALONG a power line with the voltage BETWEEN lines. Maximizing the latter will transmit same power with less current, minimizing the first and hence Ohm’s Law power loss through transmission.

Toasters kindof have to use mains voltage, there’s a kilowatt or so of power in there. They do their best to keep the mains voltage away from hands, you’d have to deliberately put your fingers in to get shocked. Always remember to switch off at the wall before you stick the knife in to dig out your crumpets!