Question

If G, and G2 in Figure P4.20 are open-collector TTL gates, state the logic input combination for which the LED will light. Assuming a diode drop of 1.6 V when on, calculate the diode current. +5 V 4 300 Ω 1u 0.1 V Time らt 4V 0.1 V Time D G2 Figure P4.20

Answer 1

1S cathode s anode e logic o a We need cathode to make LED Output of NAND Gafes G and G2 ae o if tke theis inputs are all pus are high all the low (b Assume diode dwp : 1.6v Then os loa can jo

0.0113 A 300 .. diode cusentT -(1.33 mA