R4 on the right hand side of this circiut is a 1k resistor. this simple circiut. has an intergrated circiut socket to plug the logic ic into, use a push button switch , to switch it on to test. the 2 leds alternate if the logic ic works , very handy to have and if your installing it into a circiut box ,use pins or matrix pins in place of the ic socket, on the main board and run them to an ic socket mounted onto an ic socket board which can protrude through a square hole filed into the box pannel ,so that all you have to do is plug it in and push the button to test the logic ic out
by Steven
by Steven
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