|Nanoweber per meter (nWb/m) = picoweber per millimeter (pWb/mm)|
Magnetic flux - most often denoted as Φm. The SI unit of magnetic flux
(magnetic field) is the weber (Wb) in derived units: volt-seconds.
|Enter any two values - the third will be calculated.|
|For magnetic tapes: Magnetic flux Φ in nWb/m = pWb/mm (tape flux)
Fluxivity is the amount of magnetic field that can be stored on a tape.
|The "magnetic flux density" B is the magnetic flux Φ divided by a surface (area) A:
The magnetic flux Φ is not equal to the magnetic flux density B, because the magnetic flux is not
divided by meter squared (m2)!
We use Wb/m for the track width of the magnetic tape, that is a length measure - and no area.
For magnetic tape we do not use the "magnetic flux density", as you often can find.
The magnetic flux density B in Tesla (T) is not the magnetic flux Φ in Weber (Wb)
Tape Operating Levels
Used values as standard reference flux Φ0:
150, 185, 200, 220, 250, 320, 370, or 520 nWb/m.
Maximum Output Level (MOL) performance of magnetic recording tapes at
15 ips. O = Theoretical peak flux values when aligning VU meter or PPM.
The dashed line (1955) represents the performance of the old US tape if
flux values were measured in accordance with DIN.
The Maximum Outpt Level (MOL) is the flux level at which third-harmonic
distortion reaches 3% of the fundamental's level measured at 1 kHz
(or 5% at 315 Hz for cassettes). There are a number of accepted magnetic
reference levels worldwide.
|NAB − IEC studio tape replay equalization for 38.1 cm/s = 15 inches per second (ips)
Ampex Master Equalization (AME)
Joseph Dorner: From 15 MilliMaxwell to 1200 NanoWebers
J. G. McKnight: Tape Flux Measurement Theory and Verification
J. G. McKnight: Tape Flux Measurement revisited
Choosing and Using MRL Calibration Tapes for Audio Tape Recorder Standardization
Otto Schmidbauer: Determining the Magnetization of Magnetic Tape
Quantegy Recording Solutions − Audio Recorder Setup
|tesla (T) − metric system − Unit of magnetic flux density.
Unit is named after Nikola Tesla.
Gauss (G) − cgs − Unit of magnetic flux density, that is equal to 0.0001 Tesla.
Unit is named after Carl Friedrich Gauss.
weber/square meter − Unit of magnetic flux density. 1 Wb/m2 = 1 T = 104 Gauss.
weber/square centimeter − Unit of magnetic flux density. 1 Wb/cm2 = 10000 T.
maxwell/square meter − Unit of magnetic flux density. 1 Mx/m2.
maxwell/square centimeter − Unit of magnetic flux density. 1 Mx/cm2.
1 Wb = 108 Mx. and 1 Mx = 10−8 Wb.
|Tape flux: 18.5 mM/mm = 185 nWb/m and 25 mMx/mm = 250 nWb/m|
|1 Picoweber per millimeter was 0.1 millimaxwell per millimeter|
|Weber is the practical unit of magnetic flux. It is the amount of magnetic flux which, when
linked at a uniform rate with a single-turn electric circuit during an interval of 1 second,
will induce in this circuit an electromotive force of 1 volt. Wb = V·s = m2kg/s2A.