under 50 millivolts are used and contact resistances of the order of 10 to 100 milliohms are required, gold is specified. When voltages are in the 1.0 volt or higher range, and resistances can be in the order of 5-10 ohms, nickel is considered. High voltages break through most insulating films to give adequate performance.
Even if all of the above requirements could be fulfilled by a standard or zero insertion force edge connector, selection would still not be an easy task because of the next requirement of a cartridge connector.
E. MANY MATING CYCLES
Video Games have reawakened the need for connectors that are continually used. While most edge connectors are recommended for use in the 100 to 500 cycles range, game engineers are now specifying 2,000 to 5,000 cycles as a minimum acceptable requirement. It is this requirement that causes much concern in the industry–and is leading to a new class of connector specifications. Presently available high force systems cause considerable wear, even on hard nickel surfaces. In gold based systems where forces are lower, however, wear also occurs since gold is relatively soft. Heavier than standard gold thicknesses would help solve the dilemma, but the following essential consumer product requirement would not be met.
F. LOW COST
Low cost must be evaluated two ways:
1.Purchased connector cost
2.Installed connector cost
In both respects, standard edge connectors are preferred. Zero insertion force connectors are initially more costly since they contain an additional actuating mechanism. They also cost more to fit into game packaging since the mechanism complicates game assemblies and usually requires extra parts.
We see, therefore, that design conflicts exist in chosing a Video Game connector:
STANDARD CARD EDGE CONNECTORS ARE INADEQUATE WHEN
1. Number of contacts are large.
2. Abuse is anticipated.
3. Noble metals are required.
4. Many mating cycles are specified.
ZERO INSERTION FORCE CONNECTORS ARE INADEQUATE WHEN
1. Simplicity of use is of primary concern.
2. Initial and installation costs are primary.
–94–
