Ferguson Institute Online Div. of Jmlit

Assignment #16
THE SIMPLIFIED INTERFACING PROJECTS:

The output lines or pins from our computer's I/O port chip voltages and currents are too small to be hard-wired directly to some external device like a burgular alarm switch, a temperature sensor, a stepper motor, or an auto's starter relay.  An interface is needed to protect the computer from dangerous external voltages and currents.

1.  Often TTL buffers can be used between the port and the external device.  74LS06's and 07's are very inexpensive.  

2.  A simple transistor buffer in series with a current limiter resistor will serve as a nice interface between the PC port pins and a high power AC device.

3.  A power MOSFET transistor makes an excellent interface.

4.  A newer device called a IGBT(MOSIGT) or an isolated-gate-bipolar-transistor can be a great interface.   
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EXPERIMENT: #?

DVD# 6:   HANDSHAKING and simple strobed I/O EXPERIMENT.