TESTING INTEGRATED CIRCUITS (IC's)

An Integrated Circuit is also called a "chip." It might have 8 pins or as many as 40.
Some chips are ANALOGUE. This means the input signal is rising and falling slowly and
the output produces a larger version of the input.
Other chips are classified as DIGITAL and the input starts at 0v and rises to rail voltage
very quickly. The output does exactly the same - it rises and falls very quickly.
You might think the chip performs no function, because the input and output voltage
has the same value, but you will find the chip may have more than one output and the
others only go high after a number of clock-pulses on the input, or the chip may be
outputting when a combination of inputs is recognised or the output may go HIGH
after a number of clock pulses.
Integrated Circuits can be tested with a LOGIC PROBE. A Logic Probe will tell you if a
line is HIGH, LOW or PULSING.
Most logic circuits operate on 5v and a Logic Probe is connected to the 5v supply so
the readings are accurate for the voltages being tested.
A Logic Probe can also be connected to a 12v CMOS circuit.