Voltage and Audio Amps
on
42-Volt Autos
·
· Score: 2, Informative
A higher voltage electrial system probably wont have much effect on the maximum power output of car sound systems although it may allow for more compact amplifier design. The reason for this is that car amplifiers use a DC-DC converter to generate the necessary voltages. A typical amplifier capable of delivering 100W RMS into a 4 ohm load requires about 80 volts (+40v and -40v). Even with a 42v electrical system a DC-DC converter would still be required.
I have two RH 6.2 based boxen. One is an old P133 running 2.2.22, setup as a firewall/router. This system is rock solid, uptimes are generally 90 days plus.
The other box is a P166 set up as a security camera server. Its been upgraded to 2.4.20. for better bttv support. It manages around 14 days between reboots.
Not really a fair comparision since the two systems are doing very different things but the 2.2 kernels do seem to be a little more stable
A little off topic but I have an old 40Mb Miniscribe hardrive which was removed from an IBM XT around 1987, been in storage ever since. A few weeks ago I got curious and decided to plug it in to a spare box I had lying around to see what would happen. Fairly easy since the original MFM controller and cables had been kept with the drive.
I was amazed to find that not only was all the data on the drive intact but the thing booted up straight into MSDOS 3.1 with no problems. MSDOS 3.1 and Word for DOS 5.0 really scream on a PIII 800 !
Anyway, curiosity satisfied I put the drive back in storage. I figure I'll try it again in another ten years or so... if I can still find a motherboard with ISA slots
I've never had a hard drive fail that was in storage, not counting the one that rattled around on the dashboard of my car for 6 months. I still dont think I'd recommend using them for long-term archival media though
Actually cloud seeding does work in Australia. Hydro Tasmania has been undertaking cloud seeding trials since 1964. Check out the faq at
http://www.hydro.com.au/renewableenergy/cloudsee di ng/faqs.html
The purpose of the cloud seeding is to increase rainfall in the catchment areas of hydro electric dams. Increased rainfall in these areas reduces the need to use supplementary energy sources, i.e. conventional oil fired power stations which tend to be rather expensive.
Needless to say farmers are less than impressed with these trials. They attribute unusually dry conditions experienced in the last few years on the east coast of Tasmania to these trials, claiming that Hydro Tasmania is stealing their water.
relevant qualifications tend to be a good idea. i used to blow up lots more stuff before i was properly qualified. now i can blowup just as much stuff in less than half the time. i knew getting that electronics degree was a good idea
I actually built my own power supply for my linux router/firewall. Seeing as its switched on all the time I wanted something that used convection cooling, constantly running fans piss me off. I used an old Nortel power supply board out of a telephone exchange, whacked it into a 2u rack mount enclosure and away it went. No idea what the maximum rated power output is, but its got a huge heatsink on it and barely generates any heat when powered up. uptime 90 days so far.
I suspect that a lot of computer power supplies may actually be rated by their input power rather than their output power. ie a supply rated at 300W may consume 300W of power at full load but its output would be somewhat less due to the overall efficiency of the device. Assuming an efficiency of 80% (not unreasonable for a switchmode power supply) then the maximum power output for a 300W supply would be arround 240W. One thing I find surprising about power supply ratings is that no mention is made of duty cycle. Maybe a duty cycle of 100% is assumed? Still it would be be kind of useful to know how long the power supply could cope with an overload.
Yeah, ripple voltage at full load would have been a useful test to do. I suspect the ripple voltage in my power supply is more than it should be. Seems to be manifesting itself as lots of noise though the speakers. Been gradually getting worse over the last couple of months, filter capacitors could be drying out. Might put a multimeter on it later on.
Which version of windows was used to make the comparision? Could it be that linux runs cooler because it actually makes use of the HLT instruction during cpu idle time? In an idle state my CPU runs about 15 degrees cooler in linux compared with windows 98. Using an application such as Waterfall pro or CPU Idle in windows reduces this temperature difference to almost nothing. Apparently later versions of windows do issue the HLT instruction during idle time.
Ummm, electrical devices with a poor power factor do NOT consume more power, ie they wont increase your power bill. What they will do is increase the line current to the device. But since this increased line current is out of phase with the voltage on the line no additional real power is used. Industry and electrical suppliers tend to be concerned with power factor because increased line current means you need larger conductors to supply the load which means higher cabling costs.
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A higher voltage electrial system probably wont have much effect on the maximum power output of car sound systems although it may allow for more compact amplifier design. The reason for this is that car amplifiers use a DC-DC converter to generate the necessary voltages. A typical amplifier capable of delivering 100W RMS into a 4 ohm load requires about 80 volts (+40v and -40v). Even with a 42v electrical system a DC-DC converter would still be required.
I have two RH 6.2 based boxen. One is an old P133 running 2.2.22, setup as a firewall/router. This system is rock solid, uptimes are generally 90 days plus.
The other box is a P166 set up as a security camera server. Its been upgraded to 2.4.20. for better bttv support. It manages around 14 days between reboots.
Not really a fair comparision since the two systems are doing very different things but the 2.2 kernels do seem to be a little more stable
A little off topic but I have an old 40Mb Miniscribe hardrive which was removed from an IBM XT around 1987, been in storage ever since. A few weeks ago I got curious and decided to plug it in to a spare box I had lying around to see what would happen. Fairly easy since the original MFM controller and cables had been kept with the drive.
I was amazed to find that not only was all the data on the drive intact but the thing booted up straight into MSDOS 3.1 with no problems.
MSDOS 3.1 and Word for DOS 5.0 really scream on a PIII 800 !
Anyway, curiosity satisfied I put the drive back in storage. I figure I'll try it again in another ten years or so... if I can still find a motherboard with ISA slots
I've never had a hard drive fail that was in storage, not counting the one that rattled around on the dashboard of my car for 6 months. I still dont think I'd recommend using them for long-term archival media though
Actually cloud seeding does work in Australia. Hydro Tasmania has been undertaking cloud seeding trials since 1964.
e di ng/faqs.html
Check out the faq at
http://www.hydro.com.au/renewableenergy/cloudse
The purpose of the cloud seeding is to increase rainfall in the catchment areas of hydro electric dams. Increased rainfall in these areas reduces the need to use supplementary energy sources, i.e. conventional oil fired power stations which tend to be rather expensive.
Needless to say farmers are less than impressed with these trials. They attribute unusually dry conditions experienced in the last few years on the east coast of Tasmania to these trials, claiming that Hydro Tasmania is stealing their water.
relevant qualifications tend to be a good idea. i used to blow up lots more stuff before i was properly qualified. now i can blowup just as much stuff in less than half the time. i knew getting that electronics degree was a good idea
I actually built my own power supply for my linux router/firewall. Seeing as its switched on all the time I wanted something that used convection cooling, constantly running fans piss me off. I used an old Nortel power supply board out of a telephone exchange, whacked it into a 2u rack mount enclosure and away it went. No idea what the maximum rated power output is, but its got a huge heatsink on it and barely generates any heat when powered up. uptime 90 days so far.
I suspect that a lot of computer power supplies may actually be rated by their input power rather than their output power. ie a supply rated at 300W may consume 300W of power at full load but its output would be somewhat less due to the overall efficiency of the device. Assuming an efficiency of 80% (not unreasonable for a switchmode power supply) then the maximum power output for a 300W supply would be arround 240W.
One thing I find surprising about power supply ratings is that no mention is made of duty cycle. Maybe a duty cycle of 100% is assumed? Still it would be be kind of useful to know how long the power supply could cope with an overload.
Yeah, ripple voltage at full load would have been a useful test to do. I suspect the ripple voltage in my power supply is more than it should be. Seems to be manifesting itself as lots of noise though the speakers. Been gradually getting worse over the last couple of months, filter capacitors could be drying out. Might put a multimeter on it later on.
Which version of windows was used to make the comparision?
Could it be that linux runs cooler because it actually makes use of the HLT instruction during cpu idle time? In an idle state my CPU runs about 15 degrees cooler in linux compared with windows 98. Using an application such as Waterfall pro or CPU Idle in windows reduces this temperature difference to almost nothing. Apparently later versions of windows do issue the HLT instruction during idle time.
Ummm, electrical devices with a poor power factor do NOT consume more power, ie they wont
increase your power bill. What they will do is increase the line current to the device.
But since this increased line current is out of phase with the voltage on the line no additional real power is used.
Industry and electrical suppliers tend to be concerned with power factor because increased line current means you need larger conductors to supply the load which means higher cabling costs.
Trust me, I'm an electrician