TEXT
The mating of a printed circuit board and a card edge connector is a very common occurrence in the world of electronics. Engineers and technicians are routinely careful to respect the vulnerability of the expensive hardware they handle. On the other hand, the consumer cannot be expected to do so.
The average consumer's exposure to electrical connections is limited to line cord plugs and wall receptacles, accessory cord pin and socket connectors in hand held appliances, and phone jacks. These are all ruggedly built to withstand consumer abuse, as contrasted by a p.c. board with delicate electronic components.
Video Game engineers, therefore, have a need to protect the programming boards consumers will use in second generation games. The cartridge concept appears to be the direction most games will utilize. Cartridges are already familiar to the consumer for use in 8-track and cassette tape decks and will, therefore, be readily accepted for Video Games. They also provide the required protection from abuse.
In order to understand how cartridge operated games create a need for a new class of connector, we must first examine the requirements for these connectors and then look at the standard connectors available. The basic requirements are:
A. EASE OF USE
B. PROTECTION FROM ABUSE
C. PROPER ALIGNMENT
D. ELECTRICAL STABILITY
E. MANY MATING CYCLES
F. LOW COST
Two types of p.c. board connectors are generally considered:
1. STANDARD CARD EDGE CONNECTORS
2. ZERO INSERTION FORCE CARD EDGE CONNECTORS
When we evaluate these connectors against the basic requirements for their use in Video Games, we find that each type lacks all the desired qualities. Let us explore this further:
A. EASE OF USE
Standard card edge connectors are simple for -the consumer to use since they require only a push-in or pull-out action of the cartridge. (See Figure 2) Zero insertion force connectors use the same push-in action, but they also require actuation of the contacts to mate them with the p.c. board, and deactuation to remove the board. (See Figure 3) This secondary action could be accomplished by a cammed slide, or pushbutton, or rotating knob.
When many contacts are required, standard card edge connectors are unsuitable because mating forces get too high. A 15 position 30 contact double sided card edge connector, for example, requires about 12 pounds insertion force in noble contact metal systems, and up to 20 pounds in non-noble systems. Since Video Games will be used by children, if many contacts are needed, zero insertion force connectors are preferred.
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