Transistors by themselves won't increase speed. There's nothing else than transistors and their connections. 'transistors somehow increase computation speed' All done by the same logic, from building blocks which in turn are built from transistors. You can't latch the data if you haven't given the RAM the time to place it on the bus. Yet another signal will latch that data in a register.Īn important thing is timing. Without them the controller's design would become very inefficient.) Another signal will activate the RD line (for 'read'), which signals the RAM that it should place the data on the databus. Busses are a way to get things organized. (Busses are channels of signals, an address bus for an 8-bit controller may for instance have 16 parallel wires. One of those will be to pass the RAM address to be read to the adress bus. Through a combination of gates it derives a number of signals it needs to execute the instruction. If an instruction wants to read from RAM there's first the instruction decoder. You need a building block to create a register function: a part which can hold its state, like a memory. And so it goes on, we can build an XOR gate using 4 NAND gates, and other more complex logic is built from a combination of building blocks. If either of the inputs is low at least one of the top transistors conducts and output will be made high through its connection with Vdd (that's your +). If both inputs are high the bottom transistors both conduct, and the output is made low through its connection with Vss. This is a 2-input NAND gate, you still can see some of the inverter in it. It has two or more inputs, and the output is low if all inputs are high. So if you apply a high input the bottom transistor conducts, acting as a switch, and switch the output Q to Vss (that's your -), or low level. The top transistor conducts if its input (the small dot) is low, the bottom transistor (no dot) if its input is high. The NOT gate is built with 2 transistors: The most simple gate is the NOT gate, which inverts the input level: a logic 0 becomes a 1, and vice versa. Transistors are used to make logic gates, as the lowest level building blocks. It would be pretty hard to design a modern microcontroller from the transistor level.

Cpu transistor