Hi all,

May I know how this TTL load circuit work as shown in the below diagram?

Note that: 1)the red arrow means the microcontroller control signal (1,2)
2) Is TTL output pin (3,4)

Thank you.

Best Regards
Alex.

 

What is the circuit supposed to do?
What microcontroller is sourcing the signals 1,2,3 and 4?
Can it sink a 12V signal without sustaining damage?
Can it sink enough current to activate the relays?
You need to connect suppression diodes across the relay coils.

 

What is the circuit supposed to do?
What microcontroller is sourcing the signals 1,2,3 and 4?
Can it sink a 12V signal without sustaining damage?
Can it sink enough current to activate the relays?
You need to connect suppression diodes across the relay coils.

Do you know how this circuit works?

 

May I know how this TTL load circuit work

Why do you call it that?
I see nothing that suggests it's related to TTL logic.

 

Why do you call it that?
I see nothing that suggests it's related to TTL logic.

sorry I make some mistake 3 and 4 is the TTL output

 

Can you offer any evidence that it is in fact a TTL load circuit?

 

Can you offer any evidence that it is in fact a TTL load circuit?

what evidence do you refer to?

 

Do you know how this circuit works?

The question you are asking is like showing us a paragraph from the middle of a novel and asking us to explain the plot.
The only thing I can tell from this scrap of circuitry is that the "1' and "2' are probably input signals that are capable of activating the two relays. When the lower relay is activated, it connects "3" and "4" together. I don't know what "AVDDP" means or what the sequence of the program is, so I have no idea what the rest of the circuit is supposed to do.
Why do you need this information? Is it a school project? Are you trying to repair something?

 

what evidence do you refer to?

What switching thresholds does the circuit have that might correspond to threshold for TTL logic.

 

The question you are asking is like showing us a paragraph from the middle of a novel and asking us to explain the plot.
The only thing I can tell from this scrap of circuitry is that the "1' and "2' are probably input signals that are capable of activating the two relays. When the lower relay is activated, it connects "3" and "4" together. I don't know what "AVDDP" means or what the sequence of the program is, so I have no idea what the rest of the circuit is supposed to do.
Why do you need this information? Is it a school project? Are you trying to repair something?

This is a device under test interface board circuit the ttl load is to test the max current sinking and sourcing of the semiconductor IC AVDDP is the analog power do you know how this circuit?

 

What switching thresholds does the circuit have that might correspond to threshold for TTL logic.

Do you mean microcontroller or relay switching threshold?

 

Do you mean microcontroller or relay switching threshold?

NO. I mean TTL switching thresholds. Some information you might find helpful.

A standard TTL output can drive 10 standard loads. Each load requires the output driver to sink 1.6 mA in the low state.​

TTL outputs will not typically source current. If they do source current, then the voltage level may drop significantly below the supply level.​

A logic low is any level less than 0.8V​

A logic high is any level greater than 2.0V​

 

NO. I mean TTL switching thresholds. Some information you might find helpful.

A standard TTL output can drive 10 standard loads. Each load requires the output driver to sink 1.6 mA in the low state.​

TTL outputs will not typically source current. If they do source current, then the voltage level may drop significantly below the supply level.​

A logic low is any level less than 0.8V​

A logic high is any level greater than 2.0V​

3.3V AND 5V both voltage also can be acceptable

 

3.3V AND 5V both voltage also can be acceptable

No. Standard 7400 series parts are not specified for operation at less than 4.5 VDC. If you want low voltage operation you need to look at 74HCTxx or 74LVC1Gxx parts.

 

No. Standard 7400 series parts are not specified for operation at less than 4.5 VDC. If you want low voltage operation you need to look at 74HCTxx or 74LVC1Gxx parts.

my one is not a 74series IC is an industrial IC

 

my one is not a 74series IC is an industrial IC

TTL is TTL, and that has a very specific meaning. If you don't mean that then don't use the TTL acronym. I don't know what "industrial IC" means. All of my work used "industrial ICs", and AFAIK that only means an extended temperature range. Can you be more specific?

 

TTL is TTL, and that has a very specific meaning. If you don't mean that then don't use the TTL acronym. I don't know what "industrial IC" means. All of my work used "industrial ICs", and AFAIK that only means an extended temperature range. Can you be more specific?

Actually, do you know how this circuit works?

 

Actually, do you know how this circuit works?

The resistors and diodes establish voltage levels on pins 3,4,5 & 6 on the upper group, and pins 3 & 6 on the lower group. If I knew the value of AVDDP, I could tell you what those voltage levels would be. I'm not sure what the function of K601 and K602 is, the symbols are ambiguous. When pins 1 &2 on the top of the diagram are pulled low the LED601 and LED602 will come on, Since I can't see what pins 3 & 4 at the bottom are connected to, I can't tell you much about them.

I'm pretty sure that description will not be much help to you, but you have not given us much to work with.

 

The resistors and diodes establish voltage levels on pins 3,4,5 & 6 on the upper group, and pins 3 & 6 on the lower group. If I knew the value of AVDDP, I could tell you what those voltage levels would be. I'm not sure what the function of K601 and K602 is, the symbols are ambiguous. When pins 1 &2 on the top of the diagram are pulled low the LED601 and LED602 will come on, Since I can't see what pins 3 & 4 at the bottom are connected to, I can't tell you much about them.

I'm pretty sure that description will not be much help to you, but you have not given us much to work with.

k601 k602 is a relay to control the TTL output signal flow to the power AVDDP (which needs a microcontroller to control the relay )

 

k601 k602 is a relay to control the TTL output signal flow to the power AVDDP (which needs a microcontroller to control the relay )

So is the symbol showing the contacts of the relay or the coil?