Abstract: A liquid crystal composition includes at least one compound of Formula (I) as follows:A--CH.sub.2.CH.sub.2 --B Formula (I)where A and B are substituted ring structures which include terminal alkyl groups, A being selected from: ##STR1## where R'.sub.1 is an alkyl group R.sub.1, an alkoxy group R.sub.1 O, an alkylcarbonyloxy group R.sub.1 CO.O or an alkoxycarbonyloxy group R.sub.1 OCO.O; ##STR2## where R.sub.1 is an alkyl group; or ##STR3## where R.sub.1 is an alkyl group; and B being selected from: ##STR4## where R'.sub.2 is an alkyl group R.sub.2, an alkoxy group OR.sub.2, an alkylcarbonyloxy group OCO.R.sub.2 or an alkoxycarbonyloxy group OCO.OR'.sub.2 ; and X is hydrogen or a cyano group or a methyl group or a halogen; ##STR5## where R.sub.2 is an alkyl group; or ##STR6## where R.sub.2 is an alkyl group; ##STR7## being a trans-1,4-disubstituted cyclohexane ring and ##STR8## a 1,4-disubstituted bicyclo(2,2,2)octane ring.

Abstract: Liquid crystal compositions are described which comprise a mixture of compounds and which includes at least one additive compound characterized in that the composition includes one or more additive compounds of Formula I as follows: ##STR1## wherein R.sub.1 represents an alkyl group, R.sub.2 represents an alkyl or alkoxy group or hydrogen and ##STR2## represents a 1,4-disubstituted bicyclo(2,2,2)octane ring. The preparation and properties of novel compounds of Formula I are also described. These liquid crystal compositions are useful in display devices such as digital calculators and word displays.

Abstract: A liquid crystal ester has a structure: ##STR1## where X and Y are fluorine or hydrogen at least one being hydrogen, and Z is either:(a) ##STR2## where R.sub.2 is alkyl, alkoxy, alkylcarbonyloxy or alkoxycarbonyloxy(b) ##STR3## where R.sub.3 is an alkyl group. The ester may be prepared by a conventional esterification from the corresponding phenol ##STR4## and the corresponding acid chloride Z--COCl. The ester may be used in mixtures with other liquid crystal compounds for use in known electro-optic devices.

Abstract: A novel liquid crystal compound has a formula: ##STR1## where: ##STR2## is a trans-2,5-disubstituted-1,3-dioxan ring or a 2,5-disubstituted-1,3-imidine ring ##STR3## is a 1,4-disubstituted benzene ring optionally containing one or more F, Cl or CH.sub.3 groups as lateral substituents; R.sub.1 is an alkyl group; andX is a terminal group selected from H, CN, Cl, F and R.sub.2 where R.sub.2 is selected from alkyl R.sub.3, alkoxy OR.sub.3, alkylcarbonyloxy OCOR.sub.3 and alkoxycarbonyloxy OCOOR.sub.3.

Abstract: A liquid crystal material which comprises a mixture of compounds includes at least one low viscosity additive compound of Formula (I) as follows:A--CH.sub.2.CH.sub.2 --B Formula (I)wherein A is selected from: ##STR1## and B is selected from: ##STR2##where R.sub.1 is selected from alkyl, alkoxy, alkylcarbonyloxy and alkoxycarbonyloxy; and R.sub.2 is alkyl; and where ##STR3## is a benzene ring; ##STR4## is a cyclohexane ring, which is in the trans-configuration if di-substituted; and ##STR5## is a bicyclo(2,2,2)octane ring.

Abstract: Novel liquid crystal ester compounds exhibiting a low or negative dielectric anisotropy have a structural formula: ##STR1## where R.sub.1 is an alkyl group, R.sub.2 is an alkyl or alkoxy group, ##STR2## is a 1,4-disubstituted bicyclo(2,2,2) octane ring and ##STR3## is a 1,4-disubstituted ring selected from the following: (i) a 1,4-disubstituted bicyclo(2,2,2) octane ring;(ii) a trans-1,4-disubstituted cyclohexane ring;(iii) a laterally substituted benzene ring ##STR4## where of the two groups Y and Z one is a halogen or a cyano group and the other is hydrogen or a halogen or a cyano group such that Y is the same as Z.These esters may be used in a number of known applications including liquid crystal materials for multiplexed twisted nematic devices.The esters may be made by preparative methods involving known steps.

Abstract: An intermediate useful in the production of liquid crystal esters has a molecular structure ##STR1## in which of the groups R' and R" one is fluorine and the other is hydrogen, and in which R is an alkyl group having more than one carbon atom, an aryl substituted alkyl group or a cyclohexyl substituted alkyl group.These compounds may be prepared from the corresponding alkoxy compounds ##STR2## where R'" is a protective alkyl group such as methyl. These compounds may be used in the production of liquid crystal esters by a conventional esterification with carboxylic acids, or acid derivative, eg chloride, eg containing the radical ##STR3## where X is an alkyl group and ##STR4## is a benzene or cyclohexane ring.

Abstract: Novel liquid crystal compounds exhibiting a low dielectric anisotropy have a structural formula: ##STR1## where R.sub.1 is an alkyl group, R.sub.2 is a group containing an alkyl group R and is either an alkyl group R, an alkoxy group OR, an alkylcarbonyloxy group OCOR or an alkoxycarbonyloxy group OCOOR, R.sub.1 and R containing up to 18 carbon atoms, ##STR2## is a trans-1,4-disubstituted cyclohexane ring ##STR3## or a 1,4-disubstituted bicyclo(2,2,2)octane ring ##STR4## and Ar is a 1,4 disubstituted benzene ring ##STR5## a 3-fluoro-1,4 disubstituted benzene ring ##STR6## or a 2,6 disubstituted naphthalene ring ##STR7## These compounds may be used in liquid crystal mixture compositions for use in a number of known electro-optic effects.The compounds may be prepared by routes in which the individual steps involved are known.

Abstract: A novel liquid crystal compound has the molecular structure: ##STR1## where R is an alkyl group, which may contain up to 18 carbon atoms and which may be normal or branched and may contain a chiral center, ##STR2## is a bicyclo (2.2.2) octane ring, --X-- is and Y is a cyano group CN or R.sup.1 or OR.sup.1 where R.sup.1 has the same definition as R.The compound may be used in mixtures with other liquid crystal compounds in the same or other families and the compound or mixtures may be used in known liquid crystal devices, eg the twisted nematic and cholesteric-to-nematic phase change devices, depending on its properties.

Abstract: A liquid crystal compound having the formula: ##STR1## where X is --CH.sub.2.CH.sub.2 -- or CH.sub.2 OY is ##STR2## and R is a straight or branched (possibly chiral) alkyl group having up to 15 carbon atoms.

Abstract: Liquid crystal materials are provided which are esters having the general formula: ##STR1## where n has the value 1, 2 or 3 and R is a normal or branched chain alkyl containing up to ten carbon atoms and preferably four to ten carbon atoms.These materials display a cholesteric mesophase and also a chiral smectic C mesophase underlying the cholesteric mesophase. Both of these mesophases are thermochromic.

Abstract: Novel liquid crystal compounds are disclosed, which are chiral esters based upon the phenol ##STR1## Typical examples are: ##STR2## and mixtures of these compounds have a helical pitch such that the mixtures reflect light of a specific wavelength when illuminated with ordinary light and the pitch is temperature sensitive so that the mixtures can be used in temperature indicating devices. Specific examples are given as are samples of mixtures that can be used in phase change electro-optic display devices.

Abstract: A dynamo-electric machine is provided with a protective circuit arrangement whereby the machine is caused to be switched off if a short circuit current flowing in the machine exceeds a predetermined level.False operation of the protective circuit is avoided by incorporating a discriminating circuit which is able to distinguish the phase angle between the current and the voltage. This causes the protective circuit to trip for an over load current where the phase angle difference is small and the power factor near unity, which occurs with resistive fault situations; and not to trip where the phase angle difference is high, and thus there is a low power factor indicating a reactive condition, which occurs on start-up of the machine. A machine is able to run more safely as a result.

Abstract: The present invention discloses chiral thermochromic liquid crystal mixtures which do not contain cholesterol or sterol residues.

Abstract: A dye compound suitable for use in solution with a liquid crystal material is characterized by one of the following formulae: ##STR1## (III) a derivative of (I) or (II) containing one or more simple lateral substituents or bridging groups on the benzene rings: ##STR2## where n.sub.1, n.sub.2, n.sub.3 are integers in the range 0 to 4, A is azo or azoxy, X is cyano, or nitro and Y.sub.1 and Y.sub.2 are one of the following: hydrogen, alkoxy, arylalkoxy or N.sub.R.sbsb.2.sup.R.sbsp.1 where R.sub.1 and R.sub.2 are alkyl, substituted alkyl or alkylene groups.

Abstract: A ballast circuit for coupling a lamp to an AC power source and having in series between the source and lamp a non-dissipative current limiting capacitor feeding a rectifier, the output of the rectifier being connected to a smoothing filter. The ballast lends itself particularly to use in connection with a dimmer control, and permits the use of a secondary path or bypass around the dimmer control through another capacitor feeding a rectifier formed as a diode bridge, thereby providing a minimum current level path to the lamp.

Abstract: Novel liquid crystal compounds are disclosed, which are chiral esters based upon the phenol ##STR1## Typical examples are: ##STR2## and mixtures of these compounds have a helical pitch such that the mixtures reflect light of a specific wavelength when illuminated with ordinary light and the pitch is temperature sensitive so that the mixtures can be used in temperature indicating devices. Specific examples are given as are samples of mixtures that can be used in phase change electro-optic display devices.