Will this circuit behave as I am expecting it to?
Why use CMOS (74HC02) but also Low power Schottky (74LS08)? Choose one technology and stick with that, CMOS is recommended, LS only when you have valid reasons (it is really ancient technology).

You have many floating inputs (when the switches are not pressed). Avoid that!! You must use a pull-up or pull-down resistor. Never leave inputs undefined (floating). It is a bad habit resulting from the TTL days (a floating TTL input behaved (usually) as a zero), it worked but was not recommended. For CMOS with its high impedance inputs, anything can happen on a floating node (including receiving (Russian) AM radio stations ;-) ). So tie that input up or down.

The series resistors of the LEDs are only 155 ohm

resistors come in E-series (E12, E24) so 155 ohm might not exist

155 Ohm is quite low, you're pulling ~20 mA from the outputs of the 7402 which is not recommended. If you use modern LEDs then 5 mA is more than enough to see them light up.

Also, if all the LEDs light up you're exceeding the total maximum supply current of the 74HC02 (which is around 50 mA).


The &quot;proper&quot; way is to use a transistor (BJT or MOSFET) to switch the LED's current.