Logic Gates

[ScuzZ]

Is there a simple way of converting a logic gate to say 'Transistors' or similar circuits?

 

[Nigel Goodwin]

A logic gate is usually made of transistors, so of course there is - it was done that way before IC's. You can even do it with diodes (for some gates) or relays.

 

[kein0r]

dont know if i understood you right.
Second link in google gave me http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/trangate.html

 

[cadstarsucks]

Is there a simple way of converting a logic gate to say 'Transistors' or similar circuits?

You need to be more specific... I can use gates as oscillators, as amplifiers, and comparators... what is it you want to do?

D.

 

[ericgibbs]

hi scuz,
Found the attachment while browsing my books, it may help.

Before TTL there was RTL [resistor transistor logic] and Resistor Diode logic.

Relays and Post Office stepper relay logic, infact someone posted a pix of a relay/switch bistable recently.

One of the first electomechanical/valve computers was 'Colossus' during WW2,
used to crack coded messages.

EricG

Won't attach, try again later!

 

[Nigel Goodwin]

You missed out DTL (Diode Transistor Logic).

 

[ericgibbs]

hi nigel,

I had some RDL and DTL goodies on my attempted attachment.

I gave away all my old logic gates and stuff to a guy who used to lecture
on the development history of electronics. Some 1930's Practical Wireless mags too, must be worth a bit now.

It might be worth pointing out to the 'newbies' the possiblity of expanding
the inputs on standard logic gates using resistors and diodes.

EricG

 

[AllVol]

Here's an example I found:

 

[Hero999]

Diodes are often useful when all you need is a simple AND/OR gate and a single transistor is also useful for a simple NOT gate. I wouldn't build anything more complex than a NAND/NOR gate with them though as it's cheaper to use an IC and it can get you into trouble.

 

[Zia-ul-Haq]

Yes it is possible! U can done this by using diode, transistors & resistors.

Zia-ul-Haq

 

[Papabravo]

I didn't know that the former Pakistani dictator was an electronics enthusiast. Why would anyone pay homage to such an evil slug?

 

[bananasiong]

He wants to convert logic gates to transistors or transistors to logic gates?

 

[Hero999]

Well you can't convert logic gates to transistors, it's like trying to convert a cake to eggs, flour and sugar.

 

[cadstarsucks]

Well you can't convert logic gates to transistors, it's like trying to convert a cake to eggs, flour and sugar.

That is not entirely true. An unamplified CMOS inverter is simply a complimentary pair and as such can and is used as an analog amplifier.

They are still in production today since they are popular for use in oscillator circuits, the most common of which is the common crystal osc in all our micros.

You can also use a schmidt trigger to compare an input voltage to a reference voltage reasonably well. Add a feedback resistor to adjust the dead band, an input resistor and a reference resistor.

D.