How power works in a data center: What you need to know | Circuit Breaker Parts

It turns out that the live viewfinder image doesn’t cover the full screen in 3:2 aspect mode, but is normally confined to roughly the central 80% of the available display area. When you switch to the Fn menu display, though, you need to press your eye pretty close to the viewfinder eyepiece to be able to see the menu items on the left and right sides of the screen. I found that with my eyeglasses on, I had to shift my eye to the left or the right to see the menu entries on the sides, or else really mash my eyeglasses against the eyecup. Switching to 16:9 aspect ratio expands the image to fill the left and right of the EVF’s LCD as well, which is also problematic for eyeglass wearers.

Ahh, my late, late night read of the datasheet for the MOC3041M, which the schematic initially? called out but then was changed to a MOC3041 had the mains load being carried by the MOC3041/M triac, not the BT137 triac. Good catch. The triac should still be able to handle 15 amps, not just 8. And I agree, I don’t see any heatsinking.

The Sony A33 adopts a newly developed phase-detection autofocus sensor and lens module with 15 points, of which three are cross-type. AF points can be selected automatically or manually, and both predictive control (tracking) and face detection are included, although the cameras can only focus on detected faces if they fall under a phase detection point. Autofocus working range is -1 EV to +18 EV (at ISO 100 equivalent), and there’s no dedicated AF assist lamp, with the A33 relying on low-power bursts of internal flash or an external strobe’s assist lamp for focusing in low light.

And another actually bigger reason for using DC instead of AC is when one wants x amount of mega watts of battery backed power, and converting that from DC to AC to DC again is rather inefficient, compared to just sending out the DC directly.

One possibility (on contactors) is to have a split pole with a copper ring one one half. This is similar to a shaded pole motor. The current which is induced in the copper ring (shorted winding) is out of phase with the current in the main winding and smooths out the zero crossings. Another possibility, mostly used on valves, is to rely on the inertia of the core, here the dampening effect of the fluid also helps. The device is just not fast enough to follow the 100Hz (or 120Hz in some oversea countries) ripple.

Agree on stupidity, but psychopaths have gotten an undeservedly-bad rap. See this: http://www3.nhk.or.jp/nhkworld/en/tv/firstclass/201604140600/ I’m proud to say that I scored 19 (average-level psychopath) on the the quiz that was presented.

The importance of inspection isn’t so much the wires popping off as heating up. Any signs of discoloration of the crimp terminals or wires, or any fog or smoke and you should disconnect *everything* immediately and stop using it until or unless it is repaired and ALL heat damaged components replaced and THROWN AWAY.

Earthing is thus a vital part of power distribution safety. The only snag with open equipment on your bench is that any earth connection becomes a valid part of the return circuit for the power, and since that earth connection can come through you, that’s dangerous. The isolating transformer breaks that earth circuit for your bench, thus removing that particular hazard. The upshot of this is that you can safely touch either one of the two wires and because there’s no path to ground, you won’t get zapped. (Touching two wires completes the circuit. You still have to be careful!) Isolation transformers are also used to lift the ground so that you can connect mains circuitry up to your oscilloscope, even though the black probe clip is connected to earth ground.

“Main Power” means different voltage in different places. Where I am the mains is 240 Volts and circuit layout is not acceptable for this voltage. I doubt it would even be acceptable for lower Voltage.

If you’re comfortable swapping out a circuit breaker, you can get GFCI circuit breakers as well. Protect the whole circuit at the panel.

Ok let’s assume you have a coated PCB that that doesn’t promote condensation, now unless you’re immersing your PCB in Argon, the flash over voltage is a function of the air it’s in. Unfortunately this calculation has many variables such as impurities in the air like smog (which cause condensation), altitude (which dictates how much moisture the air can carry), distance between traces (of course) and several others.

Terminals 4 and 6 are used for capacitors and/or condenser fan connections and have no electrical significance to the starting relay itself, as shown in Figure 1. In fact, terminals 4 and 6 are sometimes referred to as “dummy” terminals and are simply used for wire connections.Figure 2 shows how a potential relay is wired to a capacitor-start/capacitor-run compressor motor. Notice that the relay coil is wired in parallel with the start winding and the start capacitor.