Space heater - wire or ceramic.

[Clare Snyder]

a lot of so-called "ceramic" heaters ARE wire resistance wire encased in ceramic - just like most "quartz tube" heaters. The other outlyer is the "halogen" quartz tube heaters which use tungsten filaments in a halogen gas tube - which is then sometimes encased in a ceramic tube. I have dissassembled both resistance wire in ceramic tube and halogen lamp in ceramic tube "ceramic" heaters in recent years. Both were "cabinet" model heaters - combining radiant and fan forced - with at least one of them using sheet copper "reflectors" to focus all the heat forward and a squirrel cage plower to circulate air over the reflectors and tubes. They were NOT cheap (read that as not inexpensive) units and had all failed due to electronic control board failures - Likely fue to "cheap" Chinese electronic components

[Clare Snyder]

elements, and how few are "true ceramic". The only COMMON use I see of "true ceramic" heaters are "solid state hot plate ignitors" on gas appliances and furnaces - and there are 2 basic (common) types of THEM. Silicone Nitride and silicone carbide - with the carbide ignitors being relatively fragile, and the nitrides being MUCH more durable - particular at heat.

Real ceramic heaters draw a lot of power when cold and heat small spaces quickly (due to radiant heat?) but are not very effective for heating large areas.

[Clare Snyder]

Barium Titanate is another copound commonly used for "ceramic" heaters

- as a doping agent..

Also, technically (virtually)ALL metals have a positive temp co-efficient -with copper being about +.393% per degree C? at room temp.

60/15/25 NiChrome has a lower temp co-efficent than copper but it is still positive (could not find the spec but something like .25%/degreeC?.

The question is wheather in every-day use the temp co-effient is positive enough to reduce the current enough to keep the conductor below it's melting point at the power output required (to avoid melting town).

Even TUNGSTEN has a PTC (of only 0,0045% - but still on the POSITIVE side - - - -)

And ACTUALLY - MOST ceramics exibit a NEGATIVE temp co-effieient unless specially doped to be PTC.

NTC resistors are the ones that increase resistance and reduce current draw with temperature increase.

[Clare Snyder]

One difference between heaters is how FAST they heat up a room - and HOW they heat the room. A heater with a higher thermal was - like an oil filled heater - heat the room more slowly "from cold" but provide a more "steady" heat.

Radiant heaters heat OBJECTS in a room. Floor and ceiling heat is radiant - and with radiant ceiling heat you get cold feet sitting at a table. The table gets warm, but not your feet (or the floor under the table) Convection or fan forced (forced air) heat heats the air in the room - and it takes much longer to heat the objects in the room because they heat by conduction - from the air (which has a very low specific heat) Heating your shop with forced air takes considerable time to "get the frost out" of your tools or to heat up your car when you pull it in to work on it while radiant (hot tube) heaters warm up the floor, work bench, tools on the bench, AND the car more quickly - but do yourself a favour and turn it on for a while to heat the floor before bringing in the car, otherwize the floor UNDER the car remains FRIGID for quite some time. Once the solid surfaces heat up the air eventually catches up as all the surfaces act as "conductive heaters" to the air. When working at the hangar in the winter I like to lay out all my required tools on a bench under the heat tube for a few minutes so they fon't "frost bite" me when I pick them up. When woking at home in the garage with the electric forced air heater it takes significantly longer to warm up the tools - especially the bigger heavier stuff

[Bob F]

I don't see where the temp CO-efficient would make any difference in the efficiency of the heater. They are all still 100% efficient. Mentioning it in an ad is just BS.

[Mark Lloyd]

[snip]

Like the "constant speed motor" I saw in an ad for a cheap tape recorder.

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That must be some antique old stock. I haven't seen tape recorder cassette tape for ages.

[Clare Snyder]

They actually HAD ":constant speed motors" with a centrifical governor built in - coupled with a weighty dlywheel on the capstan flutter and speed variation (flutter and waw) could be well under .1% (Some spe'd under 0.05% which is VERY GOOD in my books) from what I remember. This was before the days of brushless DC motors and cheap synthesized synchronous AC deives

[Mark Lloyd]

An old Radio Shack catalog. IIRC, the machine was a reel-to-reel recorder with 5-inch reels (it was too small for 7-inch) and a microphone that looked like it came from 1930.

[invalid unparseable]

That old microphone must be a dynamic mic. It is quite expensive to buy dynamic mic now compared to the cheap condenser mic. Dynamic mic naturally can eliminate background noise (because you have to speak loud and close to it). That's why all singers, and recording studios use dynamic mic.

Recently I tried to buy a headset with dynamic mic for Zoom video-conference, but they are too costly for my liking.