Early TV and VCR sets had standby power and computers had a battery to power the BIOS so as to retain the programs when the main power was off. Now with flash memories which are readable, eraseable and rewriteable is this still necessary? The clock would still need power I guess but would the other functions?
I’ve been retired since 1981 and I’m a long way behind on the new hardware.
With most modern VCRs, OFF isn’t really off. As long as it’s plugged in, there’s power to run the clock, the CPU and the display, among other things. Most VCRs when unplugged will retain their settings and programming for a short time, but not indefinitely. Ditto for TVs. Computers still have a battery to run the clock, and some have a tiny battery built in to the CMOS chip to hold settings, even if the main battery is pulled. That’s the gist of things, at any rate.
I believe that CRT-based TVs have circuits to “pre-warm” the tube in standby mode so that it comes on faster. The latest LCD and plasma technologies may have knocked that requirement on the head as well.
I’ve been suspicious of the OFF button on certain appliances. Is there much of a difference in energy consumption between a VCR that is turned on or off (if not tape is playing)? Is the on/off button there because not having one would cause too many calls to the service desk?
One reason you can’t have just flash memory only for devices like computers for saving settings when they are turned off is that the clock won’t tick! That requires a power source, such as a battery, and as long as you have a battery, etc. you might as well use it for saving some other stuff.
Yes, I know the clock needs power as I said in the OP. And of course, a memory by itself isn’t much use and something is needed to operate the program stored in the memory so standby power is needed to run the processor.
My question arose because my camera doesn’t need power to keep the pictures in memory, but if I had thought about it a little, more power is required if you want to do anything with them.
Now another question. I had to buy (sob) a new VCR recently and when I turned it on and went to “clock set” the clock set itself to the correct time. Where did it get the correct time?
Probably from Boulder, Colorado, the National Institute of Standards.
They broadcast a standard time signal on several radio bands. Newer electronics often contain a small antenna inside which picks up this signal, and components that use that to automatically set the clock, reset it after power failures, adjust for daylight saving time, etc.
This was added because it makes your VCR ‘better’ than the competitors, because it automatically does something that proved to be difficult for consumers to do themselves. And it’s cheap to do with modern technology.
The last VCR I bought (The Sony SLV-N51) had an automatically set clock. Taking a look at the manual, it says that it uses a time signal sent out by some TV and Cable channels alongside the broadcast. Further down the page, as it gives step by step instructions for setting the auto set feature, it suggest using a PBS affiliate channel as the channel of choice.
What I find annoying are appliances with “off” lights. I have two stereo receivers with little red pilot lights that come on when the unit is off and go off when the unit is on. They’re labelled “standby,” which I supposed is intended to remind me that when I think the thing is off, it’s really standing by. But why, and who cares? It’s silly and illogical.
I understand the need to have power supplied when the unit is not operating, but from the point of view of the user, why bother making the distinction between “standby” and “off” with a light that is the reverse of the operating status? Pilot lights used to indicate that the unit was on, not off.