The TTL output stage is a rather complicated pushâpull circuit known as a totem-pole output (the transistors, diode, and resistor in the right-most slice of this TTL logic gate circuit). It sinks currents better than it sources current.
The theory for spontaneous generation refers to the idea that life can produced from nonliving things. Lazzaro Spallanzani proposed in his experiement that air was necessary for spontaneous generation.
Spallanzani SpalÂ·lanÂ·zaÂ·ni (spÄl'Én-zÃ¤'nÄ, spÃ¤l'lÃ¤nt-sÃ¤'nÄ), Lazzaro. 1729-1799. Italian physiologist who disproved the theory that microorganisms do not generate spontaneously. He is also noted for his research on circulation and digestion.