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 was an Italian priest born in 1729. In his early life, his father was a lawyer, and he wanted his son to do the same. However, Spallanzani showed no interest in law, and would rather do things related to animals and science. Later in life he became a priest, while also studying science.