Editing Logic gate (section)

=== Non-electronic logic gates ===
Non-electronic implementations are varied, though few of them are used in practical applications. Many early electromechanical digital computers, such as the [[Harvard Mark I]], were built from [[relay logic]] gates, using electro-mechanical [[relay]]s. Logic gates can be made using [[pneumatic]] devices, such as the Sorteberg relay or mechanical logic gates, including on a molecular scale.<ref>{{cite web |author-link=Ralph C. Merkle |author-first=Ralph C. |author-last=Merkle |title=Two Types of Mechanical Reversible Logic |date=1993 |publisher=[[Xerox PARC]] |url=http://www.zyvex.com/nanotech/mechano.html}}</ref> Various types of fundamental logic gates have been constructed using molecules ([[molecular logic gate]]s), which are based on chemical inputs and spectroscopic outputs.<ref>{{Cite journal |last1=Erbas-Cakmak |first1=Sundus |last2=Kolemen |first2=Safacan |last3=Sedgwick |first3=Adam C. |last4=Gunnlaugsson |first4=Thorfinnur |last5=James |first5=Tony D. |last6=Yoon |first6=Juyoung |last7=Akkaya |first7=Engin U. |date=2018 |title=Molecular logic gates: the past, present and future |url=http://xlink.rsc.org/?DOI=C7CS00491E |journal=Chemical Society Reviews |language=en |volume=47 |issue=7 |pages=2228–2248 |doi=10.1039/C7CS00491E |pmid=29493684 |issn=0306-0012|hdl=11693/50034 |hdl-access=free }}</ref> Logic gates have been made out of [[DNA]] (see [[DNA nanotechnology]])<ref>{{cite journal |author-first1=Milan N. |author-last1=Stojanovic |author-first2=Tiffany E. |author-last2=Mitchell |author-first3=Darko |author-last3=Stefanovic |title=Deoxyribozyme-Based Logic Gates |journal=[[Journal of the American Chemical Society]] |volume=124 |issue=14 |pages=3555–3561 |date=2002 |doi=10.1021/ja016756v |pmid=11929243 |bibcode=2002JAChS.124.3555S |url=https://pubs.acs.org/doi/abs/10.1021/ja016756v|url-access=subscription }}</ref> and used to create a computer called MAYA (see [[MAYA-II]]). Logic gates can be made from [[quantum mechanical]] effects, see [[quantum logic gate]]. [[Photonic logic]] gates use [[nonlinear optical]] effects.

In principle any method that leads to a gate that is [[functionally complete]] (for example, either a NOR or a NAND gate) can be used to make any kind of digital logic circuit. Note that the use of 3-state logic for bus systems is not needed, and can be replaced by digital multiplexers, which can be built using only simple logic gates (such as NAND gates, NOR gates, or AND and OR gates).