SUMMARY

A commercial digital IC tester is out of reach of hobbyist.Though it may not have all the facilities of a commercial Ic tester, one can test all type of gates.NOT,AND,NAND,OR,NOR,XOR,XNOR and also 555,741,358 Ics.It has been designed for testing 14 pin Ics with quad to input gates as they are commonly used Ics.However,multiple input gates can also by connecting the remaining inputs to positive or ground.
Computing systems are everywhere.Its probably no surprise that millions of computing systems are built every year destined for desktop computers(personal computers or PCs),work statins,mainframes serves.What may be surprising is that billions of computing system are built for every year many different purposes:they are embedded within larger electronic devices repeatedly carrying out a particular functio,often going completely unrecognised by the devices’s user.Creating a precise definition of such embedded computing systems,or symply embedded systems,it is not an easy task.We might try the following definitions:An embedded system is nearly any computing system other than a desktop,laptop or mainframe computer.Embedded system are found in a variety of common elecronic devices.
Microprocessors are generally utilised for relatively high performance applications where cost and size are not critical selection criteria.Because microprocessor chips have their entire function dedicated to the CPU and thus have room for more circuitry to increase execution speed.They can achieve very high levels of processing power.However microprocessor require external memory and I/o hardware.Microprocessors are most flexible and most compact.