Home » Archimedes archive » Archimedes World » AW-1996-07.adf » !Ignotum_Ignotum » !Ignotum/Formulae/Elct
!Ignotum/Formulae/Elct
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Archimedes World » AW-1996-07.adf » !Ignotum_Ignotum |
| Filename: | !Ignotum/Formulae/Elct |
| Read OK: | ✔ |
| File size: | 06FD bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
# Physics > Electromagnetism F=BIl In a magnetic field: F=force B=field strength (known as flux density) I=current flowing l=length of wire in field F=BQv For a moving charge: F=force B=field strength/flux density Q=charge v=velocity perpendicular to field B=u0NI/l Inside a solenoid (or coil): B=field strength/flux density u0=permeability of free space=4PI�10^-7 N=number of turns I=current flowing, l=length B=u0I/2PIr Near a straight wire: B=field strength/flux density u0=permeability of free space=4PI�10^-7 I=current flowing r=radial distance from wire B=u0NI/2r In the centre of a circular coil: B=field strength/flux density u0=permeability of free space=4PI�10^-7 N=number turns, I=current flowing r=radius of coil reluctance=l/u0urA In a magnetic circuit, where: l=length u0=permeability of free space=4PI�10^-7 ur=relative permeability A=area flux=IN/reluctance Where: I=current N=number of turns E=N(df/dt) In induction, where: E=induced emf N=number of turns df/dt=rate of change of flux E=M(dI/dt) In induction, where: E=emf in secondary M=mutual inductance dI/dt=rate of change of current V=L(dI/dt) In induction, where: V=potential difference across coil L=self inductance dI/dt=rate of change of current Es=VpNs/Np In transformers, where: Es=emf in secondary Vp=potential difference across primary Ns and Np=number of turns in secondary or primary IpVp>IsEs In transformers, where: Ip and Is=currents in primary/secondary Vp=potential difference across primary Es=emf in secondary Irms=I0/2^� For alternating current, where: Irms=root mean square of the current I0=peak current 2PIf=w=1/(LC)^� For electrical oscillation, where: f=resonant frequency w=angular frequency L=inductance C=capacitance
00000000 23 20 50 68 79 73 69 63 73 20 3e 20 45 6c 65 63 |# Physics > Elec| 00000010 74 72 6f 6d 61 67 6e 65 74 69 73 6d 0a 46 3d 42 |tromagnetism.F=B| 00000020 49 6c 0a 49 6e 20 61 20 6d 61 67 6e 65 74 69 63 |Il.In a magnetic| 00000030 20 66 69 65 6c 64 3a 0a 46 3d 66 6f 72 63 65 0a | field:.F=force.| 00000040 42 3d 66 69 65 6c 64 20 73 74 72 65 6e 67 74 68 |B=field strength| 00000050 20 28 6b 6e 6f 77 6e 20 61 73 20 66 6c 75 78 20 | (known as flux | 00000060 64 65 6e 73 69 74 79 29 0a 49 3d 63 75 72 72 65 |density).I=curre| 00000070 6e 74 20 66 6c 6f 77 69 6e 67 0a 6c 3d 6c 65 6e |nt flowing.l=len| 00000080 67 74 68 20 6f 66 20 77 69 72 65 20 69 6e 20 66 |gth of wire in f| 00000090 69 65 6c 64 0a 46 3d 42 51 76 0a 46 6f 72 20 61 |ield.F=BQv.For a| 000000a0 20 6d 6f 76 69 6e 67 20 63 68 61 72 67 65 3a 0a | moving charge:.| 000000b0 46 3d 66 6f 72 63 65 0a 42 3d 66 69 65 6c 64 20 |F=force.B=field | 000000c0 73 74 72 65 6e 67 74 68 2f 66 6c 75 78 20 64 65 |strength/flux de| 000000d0 6e 73 69 74 79 0a 51 3d 63 68 61 72 67 65 0a 76 |nsity.Q=charge.v| 000000e0 3d 76 65 6c 6f 63 69 74 79 20 70 65 72 70 65 6e |=velocity perpen| 000000f0 64 69 63 75 6c 61 72 20 74 6f 20 66 69 65 6c 64 |dicular to field| 00000100 0a 42 3d 75 30 4e 49 2f 6c 0a 49 6e 73 69 64 65 |.B=u0NI/l.Inside| 00000110 20 61 20 73 6f 6c 65 6e 6f 69 64 20 28 6f 72 20 | a solenoid (or | 00000120 63 6f 69 6c 29 3a 0a 42 3d 66 69 65 6c 64 20 73 |coil):.B=field s| 00000130 74 72 65 6e 67 74 68 2f 66 6c 75 78 20 64 65 6e |trength/flux den| 00000140 73 69 74 79 0a 75 30 3d 70 65 72 6d 65 61 62 69 |sity.u0=permeabi| 00000150 6c 69 74 79 20 6f 66 20 66 72 65 65 20 73 70 61 |lity of free spa| 00000160 63 65 3d 34 50 49 d7 31 30 5e 2d 37 0a 4e 3d 6e |ce=4PI.10^-7.N=n| 00000170 75 6d 62 65 72 20 6f 66 20 74 75 72 6e 73 0a 49 |umber of turns.I| 00000180 3d 63 75 72 72 65 6e 74 20 66 6c 6f 77 69 6e 67 |=current flowing| 00000190 2c 20 6c 3d 6c 65 6e 67 74 68 0a 42 3d 75 30 49 |, l=length.B=u0I| 000001a0 2f 32 50 49 72 0a 4e 65 61 72 20 61 20 73 74 72 |/2PIr.Near a str| 000001b0 61 69 67 68 74 20 77 69 72 65 3a 0a 42 3d 66 69 |aight wire:.B=fi| 000001c0 65 6c 64 20 73 74 72 65 6e 67 74 68 2f 66 6c 75 |eld strength/flu| 000001d0 78 20 64 65 6e 73 69 74 79 0a 75 30 3d 70 65 72 |x density.u0=per| 000001e0 6d 65 61 62 69 6c 69 74 79 20 6f 66 20 66 72 65 |meability of fre| 000001f0 65 20 73 70 61 63 65 3d 34 50 49 d7 31 30 5e 2d |e space=4PI.10^-| 00000200 37 0a 49 3d 63 75 72 72 65 6e 74 20 66 6c 6f 77 |7.I=current flow| 00000210 69 6e 67 0a 72 3d 72 61 64 69 61 6c 20 64 69 73 |ing.r=radial dis| 00000220 74 61 6e 63 65 20 66 72 6f 6d 20 77 69 72 65 0a |tance from wire.| 00000230 42 3d 75 30 4e 49 2f 32 72 0a 49 6e 20 74 68 65 |B=u0NI/2r.In the| 00000240 20 63 65 6e 74 72 65 20 6f 66 20 61 20 63 69 72 | centre of a cir| 00000250 63 75 6c 61 72 20 63 6f 69 6c 3a 0a 42 3d 66 69 |cular coil:.B=fi| 00000260 65 6c 64 20 73 74 72 65 6e 67 74 68 2f 66 6c 75 |eld strength/flu| 00000270 78 20 64 65 6e 73 69 74 79 0a 75 30 3d 70 65 72 |x density.u0=per| 00000280 6d 65 61 62 69 6c 69 74 79 20 6f 66 20 66 72 65 |meability of fre| 00000290 65 20 73 70 61 63 65 3d 34 50 49 d7 31 30 5e 2d |e space=4PI.10^-| 000002a0 37 0a 4e 3d 6e 75 6d 62 65 72 20 74 75 72 6e 73 |7.N=number turns| 000002b0 2c 20 49 3d 63 75 72 72 65 6e 74 20 66 6c 6f 77 |, I=current flow| 000002c0 69 6e 67 0a 72 3d 72 61 64 69 75 73 20 6f 66 20 |ing.r=radius of | 000002d0 63 6f 69 6c 0a 72 65 6c 75 63 74 61 6e 63 65 3d |coil.reluctance=| 000002e0 6c 2f 75 30 75 72 41 0a 49 6e 20 61 20 6d 61 67 |l/u0urA.In a mag| 000002f0 6e 65 74 69 63 20 63 69 72 63 75 69 74 2c 20 77 |netic circuit, w| 00000300 68 65 72 65 3a 0a 6c 3d 6c 65 6e 67 74 68 0a 75 |here:.l=length.u| 00000310 30 3d 70 65 72 6d 65 61 62 69 6c 69 74 79 20 6f |0=permeability o| 00000320 66 20 66 72 65 65 20 73 70 61 63 65 3d 34 50 49 |f free space=4PI| 00000330 d7 31 30 5e 2d 37 0a 75 72 3d 72 65 6c 61 74 69 |.10^-7.ur=relati| 00000340 76 65 20 70 65 72 6d 65 61 62 69 6c 69 74 79 0a |ve permeability.| 00000350 41 3d 61 72 65 61 0a 66 6c 75 78 3d 49 4e 2f 72 |A=area.flux=IN/r| 00000360 65 6c 75 63 74 61 6e 63 65 0a 57 68 65 72 65 3a |eluctance.Where:| 00000370 0a 49 3d 63 75 72 72 65 6e 74 0a 4e 3d 6e 75 6d |.I=current.N=num| 00000380 62 65 72 20 6f 66 20 74 75 72 6e 73 0a 0a 0a 45 |ber of turns...E| 00000390 3d 4e 28 64 66 2f 64 74 29 0a 49 6e 20 69 6e 64 |=N(df/dt).In ind| 000003a0 75 63 74 69 6f 6e 2c 20 77 68 65 72 65 3a 0a 45 |uction, where:.E| 000003b0 3d 69 6e 64 75 63 65 64 20 65 6d 66 0a 4e 3d 6e |=induced emf.N=n| 000003c0 75 6d 62 65 72 20 6f 66 20 74 75 72 6e 73 0a 64 |umber of turns.d| 000003d0 66 2f 64 74 3d 72 61 74 65 20 6f 66 20 63 68 61 |f/dt=rate of cha| 000003e0 6e 67 65 20 6f 66 20 66 6c 75 78 0a 0a 45 3d 4d |nge of flux..E=M| 000003f0 28 64 49 2f 64 74 29 0a 49 6e 20 69 6e 64 75 63 |(dI/dt).In induc| 00000400 74 69 6f 6e 2c 20 77 68 65 72 65 3a 0a 45 3d 65 |tion, where:.E=e| 00000410 6d 66 20 69 6e 20 73 65 63 6f 6e 64 61 72 79 0a |mf in secondary.| 00000420 4d 3d 6d 75 74 75 61 6c 20 69 6e 64 75 63 74 61 |M=mutual inducta| 00000430 6e 63 65 0a 64 49 2f 64 74 3d 72 61 74 65 20 6f |nce.dI/dt=rate o| 00000440 66 20 63 68 61 6e 67 65 20 6f 66 20 63 75 72 72 |f change of curr| 00000450 65 6e 74 0a 0a 56 3d 4c 28 64 49 2f 64 74 29 0a |ent..V=L(dI/dt).| 00000460 49 6e 20 69 6e 64 75 63 74 69 6f 6e 2c 20 77 68 |In induction, wh| 00000470 65 72 65 3a 0a 56 3d 70 6f 74 65 6e 74 69 61 6c |ere:.V=potential| 00000480 20 64 69 66 66 65 72 65 6e 63 65 20 61 63 72 6f | difference acro| 00000490 73 73 20 63 6f 69 6c 0a 4c 3d 73 65 6c 66 20 69 |ss coil.L=self i| 000004a0 6e 64 75 63 74 61 6e 63 65 0a 64 49 2f 64 74 3d |nductance.dI/dt=| 000004b0 72 61 74 65 20 6f 66 20 63 68 61 6e 67 65 20 6f |rate of change o| 000004c0 66 20 63 75 72 72 65 6e 74 0a 0a 45 73 3d 56 70 |f current..Es=Vp| 000004d0 4e 73 2f 4e 70 0a 49 6e 20 74 72 61 6e 73 66 6f |Ns/Np.In transfo| 000004e0 72 6d 65 72 73 2c 20 77 68 65 72 65 3a 0a 45 73 |rmers, where:.Es| 000004f0 3d 65 6d 66 20 69 6e 20 73 65 63 6f 6e 64 61 72 |=emf in secondar| 00000500 79 0a 56 70 3d 70 6f 74 65 6e 74 69 61 6c 20 64 |y.Vp=potential d| 00000510 69 66 66 65 72 65 6e 63 65 20 61 63 72 6f 73 73 |ifference across| 00000520 20 70 72 69 6d 61 72 79 0a 4e 73 20 61 6e 64 20 | primary.Ns and | 00000530 4e 70 3d 6e 75 6d 62 65 72 20 6f 66 20 74 75 72 |Np=number of tur| 00000540 6e 73 20 69 6e 20 73 65 63 6f 6e 64 61 72 79 20 |ns in secondary | 00000550 6f 72 0a 70 72 69 6d 61 72 79 0a 49 70 56 70 3e |or.primary.IpVp>| 00000560 49 73 45 73 0a 49 6e 20 74 72 61 6e 73 66 6f 72 |IsEs.In transfor| 00000570 6d 65 72 73 2c 20 77 68 65 72 65 3a 0a 49 70 20 |mers, where:.Ip | 00000580 61 6e 64 20 49 73 3d 63 75 72 72 65 6e 74 73 20 |and Is=currents | 00000590 69 6e 20 70 72 69 6d 61 72 79 2f 73 65 63 6f 6e |in primary/secon| 000005a0 64 61 72 79 0a 56 70 3d 70 6f 74 65 6e 74 69 61 |dary.Vp=potentia| 000005b0 6c 20 64 69 66 66 65 72 65 6e 63 65 20 61 63 72 |l difference acr| 000005c0 6f 73 73 20 70 72 69 6d 61 72 79 0a 45 73 3d 65 |oss primary.Es=e| 000005d0 6d 66 20 69 6e 20 73 65 63 6f 6e 64 61 72 79 0a |mf in secondary.| 000005e0 0a 49 72 6d 73 3d 49 30 2f 32 5e bd 0a 46 6f 72 |.Irms=I0/2^..For| 000005f0 20 61 6c 74 65 72 6e 61 74 69 6e 67 20 63 75 72 | alternating cur| 00000600 72 65 6e 74 2c 20 77 68 65 72 65 3a 0a 49 72 6d |rent, where:.Irm| 00000610 73 3d 72 6f 6f 74 20 6d 65 61 6e 20 73 71 75 61 |s=root mean squa| 00000620 72 65 20 6f 66 20 74 68 65 20 63 75 72 72 65 6e |re of the curren| 00000630 74 0a 49 30 3d 70 65 61 6b 20 63 75 72 72 65 6e |t.I0=peak curren| 00000640 74 0a 0a 0a 32 50 49 66 3d 77 3d 31 2f 28 4c 43 |t...2PIf=w=1/(LC| 00000650 29 5e bd 0a 46 6f 72 20 65 6c 65 63 74 72 69 63 |)^..For electric| 00000660 61 6c 20 6f 73 63 69 6c 6c 61 74 69 6f 6e 2c 20 |al oscillation, | 00000670 77 68 65 72 65 3a 0a 66 3d 72 65 73 6f 6e 61 6e |where:.f=resonan| 00000680 74 20 66 72 65 71 75 65 6e 63 79 0a 77 3d 61 6e |t frequency.w=an| 00000690 67 75 6c 61 72 20 66 72 65 71 75 65 6e 63 79 0a |gular frequency.| 000006a0 4c 3d 69 6e 64 75 63 74 61 6e 63 65 0a 43 3d 63 |L=inductance.C=c| 000006b0 61 70 61 63 69 74 61 6e 63 65 0a 0a 0a 0a 0a 0a |apacitance......| 000006c0 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a |................| * 000006f0 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a 0a |.............| 000006fd
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