140 provide leak tight electrical insulators and weldable ceramic feedthroughs fig5 shows electrical insulator assemblies 140 in detail in contrast the insulator assemblies 140 are disposed perpendicular to the plane of fig4 and hence are not shown in detail in that figure in one embodiment of electrical insulator assemblies 140 weld lips 142 are provided to be connected to housing 98 connections 142 sealingly hold insulating blocks 144 typically made of ceramic disposed through the center of insulating blocks 144 are electrical terminals 146 in this case shaped as hollow metal tubes terminals 146 extend from inside housing 98 to outside connections 142 on housing 98 inside terminals 146 electrode wires 156 158 are carried from within housing 98 to outside housing 98 solder 148 closes off in a leak tight manner the ends of terminals 146 and electrically connects electrode wires 156 158 to those terminals thus electrode wires 156 158 can be further electrically connected to external electrical equipment wires 156 158 helically cover the interior of unit 95 until they reach exit 96 of unit 95 there once outside unit 95 wires 156 158 proceed to enter one each terminals 146 as shown in fig5 wires 156 158 proceed along the outside of unit 95 to reach terminals 146 small cylindrical pieces of shrink tube 150 retain wires 156 158 and prevent contact.