Standard TTL NAND with a " totem-pole " output stage, one of four in 7400

The main advantage of TTL with a " totem-pole " output stage is the low output resistance at output logical " 1 ".

In some cases ( e. g., when the output of a TTL logic gate needs to be used for driving the input of a CMOS gate ), the voltage level of the " totem-pole " output stage at output logical " 1 " can be increased up to V < sub > CC </ sub > by connecting an external resistor between the V < sub > 3 </ sub > collector and the positive rail.

In contrast, TTL circuits with " totem-pole " output stage minimize both of these requirements.

The TTL output stage is a rather complicated push – pull circuit known as a `` totem-pole output ( the transistors, diode, and resistor in the right-most slice of this TTL logic gate circuit ).

Two-input TTL Sheffer stroke # NAND gate | NAND gate with a simple output stage ( simplified ).

The main disadvantage of TTL with a simple output stage is the relatively high output resistance at output logical " 1 " that is completely determined by the output collector resistor.

Due to the output structure of TTL devices, the output impedance is asymmetrical between the high and low state, making them unsuitable for driving transmission lines.

Several manufacturers now supply CMOS logic equivalents with TTL-compatible input and output levels, usually bearing part numbers similar to the equivalent TTL component and with the same pinouts.

Connecting a resistor between the output and the input biases the TTL element as a negative feedback amplifier.

The increased low output level can cause troubles when TTL logic circuits are driven.

In contrast, TTL circuits, while similarly modular, often require much more careful interfacing, since the limited fanout ( and fan-in ) require that the loading of each output be carefully considered.

A digital use of a push – pull configuration is the output of TTL and related families.

This is a critical advantage of TTL over DTL that speeds up the transition over a diode input structure.

Successors to the original bipolar TTL logic often are interchangeable in function with the original circuits, but with improved speed or lower power dissipation.

Standardization of the TTL levels was so ubiquitous that complex circuit boards often contained TTL chips made by many different manufacturers selected for availability and cost, compatibility being assured ; two circuit board units off the same assembly line on different successive days or weeks might have a different mix of brands of chips in the same positions on the board ; repair was possible with chips manufactured years ( sometimes over a decade ) later than original components.

An external TTL register was often used for sequential designs such as state machines.

Just inspecting the Initial TTL and window size fields is often enough in order to successfully identify an operating system, which eases the task of performing manual OS fingerprinting.

* The TTL field of IPv4 has been renamed to Hop Limit, reflecting the fact that routers are no longer expected to compute the time a packet has spent in a queue.

Frequently starting with a value like 128 ( Windows ) or 64 ( Linux ), routers decrement this and discard a packet when the TTL value has reached zero, returning the ICMP error message ICMP Time Exceeded.

If a stub resolver queries the caching nameserver for the same record before the TTL has expired, the caching server will simply reply with the already cached resource record rather than retrieve it from the authoritative nameserver again.

Since the invention of the “ solid state ” transistor in the 1950s and the TTL ( transistor-transistor logic ) that led to the development of the IC ( integrated circuit ) in the 1960s the growth in the field of electronics has been phenomenal.

Compared to contemporary ECL circuits, TTL uses less power and has easier design rules but is substantially slower.

Variations of and successors to the basic TTL family, which has a typical gate propagation delay of 10ns and a power dissipation of 10 mW per gate, for a power – delay product ( PDP ) or switching energy of about 100 pJ, include:

V < sub > CC </ sub > and Ground are carryovers from TTL logic and that nomenclature has been retained with the introduction of the 54C / 74C line of CMOS.

TTL has been used on a range of other Mazda vehicles before and since the MX-3.

TTL introduced a new brew, Taiwan Beer Gold Medal, by the end of its first year and has since introduced three more brews: Taiwan Beer Draft ( another lager, for sale in restaurants ) and two malt beers under the Mine label ( Amber and Dark ).

Any and all signals inside a device that has RS232 connectivity are always TTL level ( 0 and 5V or 0 and 3. 3V or 0 and 3v ) internally and conversion to and from RS232 is the last thing outgoing data does, or the first thing incoming data does.

TTL has changed significantly over the years, with newer versions replacing the older types.

They form a replacement for TTL, although HCT is slower than original TTL ( HC logic has about the same speed as original TTL ).

The shutter dial of the M6 TTL is reversed from previous models, turning in the same direction as the light meter arrows in the viewfinder ; this feature has continued in the M7, M8, and M9, but not the MP, which returned to the older, smaller diameter, opposite direction shutter speed dial.

This switch in the TTL approach has shifted its emphasis more towards BTL.

Each node, upon receiving a RouteRequest packet, rebroadcasts the packet to its neighbors if it has not forwarded it already, provided that the node is not the destination node and that the packet ’ s time to live ( TTL ) counter has not been exceeded.

It has a voltage swing between 0. 4 volts and 1. 2 volts — much lower than that used in TTL and CMOS logic — and symmetrical parallel resistive termination.

Therefore, IPv6 routers do not need to recompute a checksum when header fields ( such as the time to live ( TTL ) or hop count ) change.

or, when powered from a unipolar TTL / CMOS power supply:

The first SLR cameras with internal (“ through-the-lens ” or “ TTL ”) meters ( e. g., the Pentax Spotmatic ) required that the lens be stopped down to the working aperture when taking a meter reading.

The designation TTL is sometimes used to mean TTL-compatible logic levels, even when not associated directly with TTL integrated circuits, for example as a label on the inputs and outputs of electronic instruments.

A TTL input signal is defined as " low " when between 0 V and 0. 8 V with respect to the ground terminal, and " high " when between 2. 2 V and 5 V ( precise logic levels vary slightly between sub-types and by temperature ).

Consequently, CMOS devices do not produce as much waste heat as other forms of logic, for example transistor-transistor logic ( TTL ) or NMOS logic, which normally have some standing current even when not changing state.

A short TTL on the A-record helps to ensure traffic is quickly diverted when a server goes down.

The HP 9810, 9820 and 9830 desktop computers used a slow, serialized TTL version of the 2116 CPU, although they did not ultimately use any of the operating system or application software, instead relying on user-friendly ROM-based interpreters such as BASIC which worked when powered up and integrated keyboards and displays rather than disks or standard terminals.

A second advantage of differential TTL, when correctly terminated, is that the differential pair of wires forms a current loop.

In contrast to TTL, CMOS uses almost no power in the static state ( that is, when inputs are not changing ).

The 7407 TTL device, an open collector buffer, simply outputs whatever it receives as input, but as an open collector device, the output is left effectively unconnected when outputting a " 1 ".

The analog version of TTL works as follows: when the incoming light hits the film, a part of it is reflected towards a sensor.