LEFT is "NAND" Gate and Right is "AND" Gate. NAND and AND Gate is required to have ALL inputs as + to affect the output. The transistors are in SERIES, and diodes are in facing negative. The AND gate is diode logic.
INPUTS(BLUE LED) OUTPUT/RESULTS(RED LED)
NAND AND
- - + -
+- + -
-+ + -
++ - +
