Is the AC AC or DC?
It’s AC in case it’s not just for fun.
Well, in DC the AC is certainly AC.
If you offered someone and AC that ran on DC, they’d be thunderstruck.
If only we could. Purchase, plug into wall, works with utter reliability for a decade or more with no maintenance other than the occasional wipe down with a wet cloth. It’s a dream, I tell you. A beautiful dream!
My mother is still using the cheap-ass microwave my sister and I bought her for Christmas sometime in the late eighties.
It should be noted that in most appliances today (AC powered electronic stuff), there are actually three stages of conversion between AC and DC and vice-versa; first you have a rectifier to produce DC, then a switch-mode power supply converts the DC voltage into AC via a transformer (not AC in the “traditional” sense, as the transformer primary is driven only one way, except in higher-power converters) and then this AC is rectified back to DC (although again not really AC; if you need a negative output, you need another winding on the transformer, not just a reversed diode). Many higher-power supplies also add a power-factor correction stage between the rectified AC input and SMPS for an additional stage of conversion to simulate a resistive load.
This is done because it is smaller, lighter, and more efficient than using a 60 Hz step-down transformer and regulator; small AC transformers are notoriously inefficient (check out the ratings on a non-SMPS AC adapter sometime; looking at one I have on hand right now, it is rated at 12 watts input and 4 watts output for an efficiency of 33%; these also have a quite high no-load power draw). Also of interest, most SMPS designs can run on DC power with no problems, except for those with a voltage selection switch (and those would still work if set to 230 volts; 115 volts uses a voltage doubler which needs AC to work).
Originally Edison distributed only DC (it is said that he didn’t understand AC, but it is likelier that there were some patents he didn’t want to pay royalties on). In 1960 my then girl-friend lived in an apartment at 103 St. and B’way in NYC that still had DC power. Lights and toasters didn’t care what you fed them (and there were radios made for DC that had a set of vacuum tubes with heater voltages that totaled to 117) but virtually everything else was made for AC operation. So she had a generator in a closet that ran a DC motor driving an AC generator to power all the other appliances. Noisy as hell. I don’t know when they changed.
If you want to see the AC spin a coin (a quarter works very well) on a table under a fluorescent bulb. You see strobe patterns slow down, stop, speed up as it winds down. Just like the wagon wheels in old westerns. Although that is the result of the frame rate of movies, since the sun operates in DC mode.
This is why you do not want to use a fluorescent tube for lighting your lathe. At certain revs it will look like the headstock is still even though it is spinning. Eventually you will block out the noise of the motor and put your hand into it.
At a certain power station many years ago they held an open day and had to label a rotating machine prominently to warn people this was happening. Naturally someone had to test the truth of this statement by putting his hand into it.
Many modern fluorescent fixtures now use electronic ballasts which don’t have power line flicker because they use a converter which runs off of rectified and filtered AC (the tube is driven at 10s of kHz, essentially producing continuous light; the plasma discharge and phosphors also have a short persistence time), so this is probably less of a problem, although older magnetic ballasts are still in widespread use.
Really you don’t need AC …At All ! The reason appliances run on AC ( really DC !!) is so they can control you.They can charge you a fortune and tell you how hard it is to create and then push all that AC across thousands of miles. Nicholas Tesla wanted a home base DC system not an AC system that has to be pushed 1,000’s of miles. When Tesla died all his work was seized .
Who’s “they”? The Illuminati? The Martians?
If you are going to reply to an old thread, at least post something that isn’t complete BS, OK?
Since this is an old thread that has been raised for no good reason, I’m closing it.
Colibri
General Questions Moderator