Fourth year first PLC test resources

Here are a couple of more resources for  logic gates and number conversion.  Remember you have a tech math text and workbook that covers this.

http://www.kpsec.freeuk.com/gates.htm  has logic gate explanation

http://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html   has a calculator to convert binary-decimal-hex so you can make your own problem and know the solution.