Logic can explain difficult-to-understand concepts to people who are ignorant to pieces of data to support a conclusion. Logic cannot, however, convince someone that something… they are stubborn to accept to be true. (MORE)
TTL Logic .
To know about the advantages of TTL logic family, one should have a basic idea about RTL, DTL etc. Diode logic (DL) uses diodes to implement logical functions l…ike AND and OR. But the disadvantage is that it can not perform NOT operation. As AND and OR are not complete functions by themselves, they can not perform several logic functions without NOT. Hence, there was a need for some device which can perform a NOT function as diodes can not. That device is a transistor. Then came the DTL which uses a transistor along with diodes. As a transistor can act as an inverter, NAND (NOT-AND) & NOR (NOT-OR) operations can be performed. But this logic uses several diodes which will slow down its operation. Due to the delay offered by them, the logic levels may sometimes change i. e. 0 t0 1 or 1 to 0. Then came TTL. This logic uses a multi emitter transistor, a transistor with many emitter terminals. As every emitter is nothing but a diode, this logic eliminates the use of all diodes. This is the major advantage. As transistor becomes ON and OFF much rapidly than a diode, switching time will be faster..
TTL, or Transistor-transistor logic replaced resistor-transistor logic, and used much less power. The TTL family is very fast and reliable, and newer faster, less power-consuming, etc. types are always being developed..
In TTL (Transistor-Transistor Logic), think that the device using this technology is made from several transistors. Another advantage is that many more chips employ this technology. (MORE)
# One and two cross, one returns, four seconds. # Four and five cross, two returns, nineteen seconds. # Three and one cross, one returns, twenty-six seconds. # One… and two cross, twenty-nine seconds (MORE)
Here are the propagation delays for these gates a) ECL = 2ns b) TTL = 1.5-33ns depending on the type of TTL. Conventional TTL is 9ns, Advanced Schottky TTL is 1….5ns c) RTL = 25ns d) CMOS = 5-20ns depending on if it is conventional CMOS, TTL pin compatible CMOS, high speed TPC CMOS or TTL compatible CMOS So the fastest would be the Advanced Schottky TTL (74ASxx) at 1.5ns but the choice simply said TTL which I would interpret as Conventional TTL (74xx/54xx) which would have a propagation delay at 9ns. So the winner is ... (a) ECL which has a propagation delay at 2ns.(MORE)
Logic is the science of correct thinking. A classic definition is new and necessary reasoning. It's new because you didn't know the item before, and necessary because a corr…ectly formulated syllogism has to be true if the bases are true. This syllogism is a well-known example: All men are mortal. Socrates is a man. Therefore, Socrates is mortal. We took two axioms and made a new and necessary conclusion. (MORE)
Power:- TTL 5v, CMOS 1.8 to 15v. TTL much more power hungry than CMOS. CMOS more susceptible to static than TTL. CMOS power required is small especially when static and increa…ses with clocking frequency. TTL threshold levels < 0.8V low, >2.4V high. CMOS threshold levels < 50% of rail low, >50% high, therefore greater noise immunity. (MORE)