What purpose does standby serve?

[Greg]

Hello,

I have become embroiled in a discussion with government
representatives from many agencies about whether or not items such as
TVs, VCRs, DVDs etc should be turned off to conserve electricity as
opposed to leaving them turned on in standby mode.

Can someone PLEASE tell me why standby mode is used?

Why should such appliances be left in standby mode instead of turned
off?

If the appliance is turned off instead of being put into standby mode,
will the appliance's life be shortened, by how much and why?

I have seen sums on the energy savings if appliances are turned off
instead of being placed in standby, but I suspect that there is more
than this than meets the eye.

Many, many thanks,
Greg
Brisbane
Australia

 

[Harvey]

Hello,

I have become embroiled in a discussion with government
representatives from many agencies about whether or not items such as
TVs, VCRs, DVDs etc should be turned off to conserve electricity as
opposed to leaving them turned on in standby mode.

Can someone PLEASE tell me why standby mode is used?

Why should such appliances be left in standby mode instead of turned
off?

Convenience. There's nothing more annoying as having to walk 3 feet over to
the TV to switch it on (only to have it power up to *standby* so having to
then go back and search for the remote anyway). So much easier to leave it
in standby...

If the appliance is turned off instead of being put into standby mode,
will the appliance's life be shortened, by how much and why?

I doubt it makes much of any real difference. Some people say leaving items
in standby reduces the shock of the initial power on surge, others say the
heat produced in standby reduces the life by an equal or greater amount.
You'd be hard pressed to ever put any meaningful figures on it.

I have seen sums on the energy savings if appliances are turned off
instead of being placed in standby, but I suspect that there is more
than this than meets the eye.

You have to ask if all the items on standby make any significant difference
compared to.. say.. all the wasted energy used heating empty rooms in
factories, schools etc. - all of which goes to waste because most of those
buildings have no insulation whatsoever.

Things could certainly be done to reduce energy waste; but.. at the end of
the day.. nobody can be bothered much. We enjoy our lifestyles too much to
worry about things that won't directly affect us. Sad, but true.

....

 

[Sam Goldwasser]

Convenience. There's nothing more annoying as having to walk 3 feet over to
the TV to switch it on (only to have it power up to *standby* so having to
then go back and search for the remote anyway). So much easier to leave it
in standby...


I doubt it makes much of any real difference. Some people say leaving items
in standby reduces the shock of the initial power on surge, others say the
heat produced in standby reduces the life by an equal or greater amount.
You'd be hard pressed to ever put any meaningful figures on it.


You have to ask if all the items on standby make any significant difference
compared to.. say.. all the wasted energy used heating empty rooms in
factories, schools etc. - all of which goes to waste because most of those
buildings have no insulation whatsoever.

Things could certainly be done to reduce energy waste; but.. at the end of
the day.. nobody can be bothered much. We enjoy our lifestyles too much to
worry about things that won't directly affect us. Sad, but true.

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

10? 5? 2? 1?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Harvey]

[..]]

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

10? 5? 2? 1?

Ah, but how much extra energy went into the _manufacturing_ of these 'energy
efficient lights compared to incandescent lamps? I've not seen any figures
and I wouldn't really like to guess, but its got to be more; probably by a
factor or two or three...

 

[Do Litlle Jr.]

[..]]

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

10? 5? 2? 1?

Ah, but how much extra energy went into the _manufacturing_ of these 'energy
efficient lights compared to incandescent lamps? I've not seen any figures
and I wouldn't really like to guess, but its got to be more; probably by a
factor or two or three...

.... and not to forget the extra costs in manufacturing
(and eventually servicing those) standby circuits...

 

[NSM]

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

When my grandmother got her first color TV (all tube) I modified it so the
tube heaters stayed on all the time. Never took the back off until we
swapped it out for a new model many years later.

 

[Sam Goldwasser]

[..]]

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

10? 5? 2? 1?

Ah, but how much extra energy went into the _manufacturing_ of these 'energy
efficient lights compared to incandescent lamps? I've not seen any figures
and I wouldn't really like to guess, but its got to be more; probably by a
factor or two or three...

Yes, but how does it compare with the electrical energy cost over the life of the
lamp (100 kW-h for a 100 W 1000 hour incandescent lamp)?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Sam Goldwasser]

When my grandmother got her first color TV (all tube) I modified it so the
tube heaters stayed on all the time. Never took the back off until we
swapped it out for a new model many years later.

Hmmmm. Cost of electricity to run heaters: Totally rough guess of 100 W over
10 years or about 8,000 kW-h. What did electricity cost back then?
How did the cost of the electricity to keep the heaters lit continuously
compare to the cost of a service call to replace a tube?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Ken Weitzel]

When my grandmother got her first color TV (all tube) I modified it so the
tube heaters stayed on all the time. Never took the back off until we
swapped it out for a new model many years later.

Hi...

Do both! Let's save a little of the world's resources
for the next generations. Or at least as much as possible.

As for those tube filaments, back in those good old days
there were no concerns about non-renewable resources, hydro
was virtually free, and we concerned ourselves not a whit
about the environment.

Still, one of the first sets I bought (Rca, I think) left
the filaments on half voltage while the set was turned off.
They called it "instant on". Yet there was a holiday
switch on the back that shut it down completely.

Take care.

Ken

 

[James Sweet]

[..]]

Well, maybe.

But consider: Replacing how many 100 W incandescent lamps used 6 hours
a day with 25 W equivalent brightness compact fluorescents will it take
to same more energy than used by all those appliances in the house with
standby modes?

10? 5? 2? 1?

Ah, but how much extra energy went into the _manufacturing_ of these 'energy
efficient lights compared to incandescent lamps? I've not seen any figures
and I wouldn't really like to guess, but its got to be more; probably by a
factor or two or three...

Yes, but how does it compare with the electrical energy cost over the life of the
lamp (100 kW-h for a 100 W 1000 hour incandescent lamp)?

Really depends, if you buy the garbage LOA CFL's and they die after 3 weeks
then it's not a very good investment. My entire house has been CFL for
several years now aside from the diningroom chandelier and since I did the
swap my electric bill dropped noticeably. For lights like porchlights and
others that are on for extended periods of time it's silly to use an archaic
incandescent lamp.

 

[William R. Walsh]

Hi!

Can someone PLEASE tell me why standby mode is used?

There are a few reasons.

1. It allows for easy addition of a remote control circuit. By leaving the
microcontroller and a sensor active, a remote is easily added to a design.
2. It removes the need for a separate memory device and a means to power
it...at least until the power goes out!
3. Some designs use it for a quicker start-up time.
4. A device can be turned on from standby using a special "power up" command
or timer event. WebTV boxes do this.

Why should such appliances be left in standby mode instead of turned
off?

For the ones with volatile memories backed by the power line and a portion
of the power supply, the answer is obvious...remove power entirely and the
memory goes away. For others with remote controls the answer is also
obvious...something has to be on and "watching" for remote power-on signals.

For some devices there is no good reason and unplugging them won't harm a
thing.

I don't know if turn-on cycles without the "aid" of a standby supply are
more stressful to the other electronics in a device or not. Given that most
everything is turned off and started "cold" by the few parts that do remain
on, I would have my doubts that standby modes could increase the life of a
device.

Devices with "hard" on-off switches are usually a little bit better
protected than those which are always "on" or in standby. This does depend
on the location of the switch though.

If the appliance is turned off instead of being put into standby mode,
will the appliance's life be shortened, by how much and why?

I doubt that it would be. There are a lot of factors here. First, some
devices will fail in standby because the wear on a small part of the device
is constant. This can lead to dried up capacitors or other failed
components.

Starting any device is a stressful time on all the components involved.
Things are starting up and stabilizing. Usually this doesn't affect the
device's life significantly as you've got to turn on it on sometime!

William

 

[NSM]

Hmmmm. Cost of electricity to run heaters: Totally rough guess of 100 W over
10 years or about 8,000 kW-h. What did electricity cost back then?

About 3 cents per KWh.

How did the cost of the electricity to keep the heaters lit continuously
compare to the cost of a service call to replace a tube?

I'd have been doing the replacing and the kine ran till the set died. They
didn't all do that, for sure, I replaced my share for other people. That's
how the old tube computers kept going too, keep the filaments alive.

 

[NSM]

Hi...

Do both! Let's save a little of the world's resources
for the next generations. Or at least as much as possible.

As for those tube filaments, back in those good old days
there were no concerns about non-renewable resources, hydro
was virtually free, and we concerned ourselves not a whit
about the environment.

Wouldn't bother now, but we were 100% hydro back then. Might have saved the
earth by cutting down on waste material for the sake of a few gallons of
rain water.

 

[James Sweet]

About 3 cents per KWh.


I'd have been doing the replacing and the kine ran till the set died. They
didn't all do that, for sure, I replaced my share for other people. That's
how the old tube computers kept going too, keep the filaments alive.

Doesn't keeping the filaments heated boil off emissive material from the
cathode? I haven't had a ton of vacuum tube equipment but of 2 dozen or so
bad tubes I've replaced, only *one* of them had an open filament.

 

[Ken Weitzel]

Wouldn't bother now, but we were 100% hydro back then. Might have saved the
earth by cutting down on waste material for the sake of a few gallons of
rain water.

Hi NSM...

Ahh, if you're definition of hydro is electricity then you're
surely right.

But if hydro means "falling water generated" then I beg to
disagree. Vast quantities of electricity was generated by
burning coal. And that meant burning fuel for earth digging
machines to uncover it. Burning fuel for gas powered conveyor
belts to move it. More fuel for trucks to take it to the
rail lines. Then coal burning smoking smelly dirty locomotives
to move it around the country. Then more trucks, and on and on
and on. Bad news.

Now if each of those filaments was - say 5 watts? - and a
dozen tubes minimum per set - then 60 watts per set 24/7.

Imagine if we did that today

Take care.

Ken

 

[Jerry G.]

Standby mode, is to keep the computer sectons in the appliances active,
so that it can economicaly keep the setups. It also allows for the unit
to be able to keep track of the time of day, and economicaly maintain
the user parameters.

In the standby mode, some devices use a separate standby supply, or
have the main supply go to a low power output mode. Some appliances
pull less than 1/2 a Watt in the standby mode. Some larger appliances
are as high as 2 to 3 Watts in the standby mode.

In the appliances that share the operation of the main power supply for
both the standby and operation mode, tend to have their power supply
last longer. This is because the supply is still internaly active, but
there is very little load on it.

It is also a known fact, that devices that are left running all the
time, tend to have the components last longer. The sudden inrush of
current, and the temperature variations are what reduces the lifespan
of many electrical devices. For CRT type devices, the life span of the
CRT is reduced if the CRT is left running with beam current.

CRT's have a restricted life span, which is mainly determined from the
beam current. On a TV set, if you want to leave it left on, you can
turn down the brightness and contrast to minimum, and this would make
it have a reduced cathold current. The reduced cathold current would
increase the tube's lifespan. Since there is alway some cathold current
when there is high voltage, this will only be an extension on its
lifespan. The heater's rarely burn out in CRT's.

If you use a device every day, or even a few times a week, leaving it
in standby would allow for the unit to start up easier, and without the
user re-entering in all his paramters.

Using a chargeable battery to maintain the user parameters, would then
have the need for the power to be maintained at times to keep the
battery charged. Then after a time, these batteries would have to be
replaced, and thus end up as an added physical polution to the
environment.

In the standby mode, most of these appliances pull the same, or less
current than a wall clock. Infact, a VCR or TV set in standby generaly
will not pull enough current to get the power consumption meter from
the power company to even take a reading of the consumption.

If you want to, get an AC bar to feed your devices. You will have to
re-set it up every time you want to use it.

 

[Jerry G.]

Standby mode, is to keep the computer sectons in the appliances active,
so that it can economicaly keep the setups. It also allows for the unit
to be able to keep track of the time of day, and economicaly maintain
the user parameters.

In the standby mode, some devices use a separate standby supply, or
have the main supply go to a low power output mode. Some appliances
pull less than 1/2 a Watt in the standby mode. Some larger appliances
are as high as 2 to 3 Watts in the standby mode.

In the appliances that share the operation of the main power supply for
both the standby and operation mode, tend to have their power supply
last longer. This is because the supply is still internaly active, but
there is very little load on it.

It is also a known fact, that devices that are left running all the
time, tend to have the components last longer. The sudden inrush of
current, and the temperature variations are what reduces the lifespan
of many electrical devices. For CRT type devices, the life span of the
CRT is reduced if the CRT is left running with beam current.

CRT's have a restricted life span, which is mainly determined from the
beam current. On a TV set, if you want to leave it left on, you can
turn down the brightness and contrast to minimum, and this would make
it have a reduced cathold current. The reduced cathold current would
increase the tube's lifespan. Since there is alway some cathold current
when there is high voltage, this will only be an extension on its
lifespan. The heater's rarely burn out in CRT's.

If you use a device every day, or even a few times a week, leaving it
in standby would allow for the unit to start up easier, and without the
user re-entering in all his paramters.

Using a chargeable battery to maintain the user parameters, would then
have the need for the power to be maintained at times to keep the
battery charged. Then after a time, these batteries would have to be
replaced, and thus end up as an added physical polution to the
environment.

In the standby mode, most of these appliances pull the same, or less
current than a wall clock. Infact, a VCR or TV set in standby generaly
will not pull enough current to get the power consumption meter from
the power company to even take a reading of the consumption.

If you want to, get an AC bar to feed your devices. You will have to
re-set it up every time you want to use it.

 

[w_tom]

William provided good answers. As for life expectancy, a
cold power up or from standby means the same components do a
complete 100% power up. There is no stress reduction on power
up from standby. AND that stress from powerup becomes (for
all practical purposes) mythical once we apply more numbers.

Standby tends to draw about 7 watts constantly waiting for
you to make a decision. 7 watts is the difference between
standby and a cold powerdown - see manufacturer datasheet for
a more accurate number. If the discussion with that
government representative did not provide that number, then
you were both wasting time. Without numbers, then the
discussion could only resort to wild speculation.

 

[w_tom]

In a system that consumes tens or hundreds of watts, then
1/2 watt for standby mode is the exact same thing as zero
power to those components. Standby does not extend equipment
life expectancy. Components suffer a 100% power increase
whether from standby mode or from cold restart.

It is nonsense to think that trivial current of standby mode
will save a component. Moreso, please tell us what the
current is through which parts so that parts last longer.
What are the numbers? And good luck trying.

As for time - computer maintains time of day in a circuit
completely unrelated to standby power. That design dates back
to the first IBM AT that had no standby option. Again, first
learn circuits before posting how they work.

Powering up from standby mode is no 'easier' on hardware
than powering from cold restart. The power up is different,
but just as 'stressful'. Stressful in quotes because the
stress from power up is mostly mythical - often promoted by
those who did not first learn how components work.

 

[Gary J. Tait]

Doesn't keeping the filaments heated boil off emissive material from the
cathode? I haven't had a ton of vacuum tube equipment but of 2 dozen or so
bad tubes I've replaced, only *one* of them had an open filament.

Most tube sets I came across had their standby reduce the current
going through the filaments.