Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

hex inverter out of discrete RTL or TTL

Status
Not open for further replies.
neazoi

neazoi

Advanced Member level 6
Joined
Jan 5, 2008
Messages
4,122
Helped
13
Reputation
26
Reaction score
15
Trophy points
1,318
Location
Greece
Activity points
36,951
hello I need to make a hex inverter out of transistor transistor logic or better transistor resistor logic. anyone could help?
I need to substitute the mc789ap chip
 

Do you know the characteristics of the MC789? Voltage levels, power supply, drive current etc?

Keith.
 

keith1200rs said:
Do you know the characteristics of the MC789? Voltage levels, power supply, drive current etc?

Keith.
Click to expand...

No keith. I cannot find the datasheet. But it is TTL, so the voltage levels should be compatible with TTL. I would say drive current is not of much importance to my application.
It would be fun If I could build a hex inverter out of transistors instead. maybe it is just as simple as the attached image (although RTL) but I just want to make sure.
This is two input, but it can be converted to one if using just one transistor I think
 

I was thinking of something like this:

94_1281001384.gif


Keith.

What you have drawn is a NAND gate, not an inverter.

Keith
 

    neazoi

    neazoi

    Points: 2
    Helpful Answer Positive Rating
keith1200rs said:
I was thinking of something like this:

94_1281001384.gif


Keith.

What you have drawn is a NAND gate, not an inverter.

Keith
Click to expand...

yes, if you connect two inputs together it becomes an inverter :)

What about the next one which is simpler and using just one transistor? Please omit one of the two resistors, they are from another application.
The output goes to zero if a one has been received.
 

Yes, a simple transistor inverter with resistive load would work. You probably need to put a resistor from base to ground because it would start to turn on at 0.8V - a TTL low. Around 10k would do.

Keith.
 

    neazoi

    neazoi

    Points: 2
    Helpful Answer Positive Rating
neazoi said:
What about the next one which is simpler and using just one transistor? Please omit one of the two resistors,
Click to expand...
It works. Why dont you try to simulate it? You will see and make sure that it works.
Here is an example one transistor inverter and its transfer characteristic:
**broken link removed**
**broken link removed**

One thing to consider, how fast your inverter is supposed to work. You may need fast transistors.
 

    neazoi

    neazoi

    Points: 2
    Helpful Answer Positive Rating
hm.. I am reading some articles now.. This DTL has to be better in terms of noise immunity and speed..
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top