KISS,
Thank your for providing your drawing. I am looking at it now and will see if I can find Spice models for the parts that are not available in Multisim.
I however have a couple of dumb questions:
1. Resistors for LEDS – I do not totally understand the specs you have provided. [i.e. ~=(5-1.2)/20e-3ohms.] I believe this may be a formula, but I am not exactly sure if it is or not. My guess is as follows:
...a. My guess to the various part of this are
......i. 5 stands for 5Volts.
......ii. 1.2 must be some Ohms Law value or something.
......iii. 20e – not a reasonable clue here.
......iv. 3 ohms – This one is ohms, but I am not sure what it applies to…
...b. So if it is a formula it is saying (5 minus 1.2) div by 20e minus 3 ohms. Or it is a DVR Code to record a TV show sometime next week…
2. 74HCT05 -
...a. Multisim has the old 74HC05D_6V, which I know has some internal differences, but do you thing they are similar enough to be substituted in the simulation only or will this not work for the simulation?
...b. Through Hole Package – Unless I am mistaken, I found MM74HCT05N should be correct for Through Hole Sodering or pushing in a socket. Does this sound about right?
3. LEDs & Opto Relays in Series –
...a. I assume Anode between 74HCT05 output and before LCC110 pin #3 input, with Cathode to Ground. (No Resistor required???) This will not pull needed Current away from the 74HCT05 #3 and cause any problems, Right?
4. Analog & Digital Grounds Separate – I am not sure what the laws are here to create separation.
...a. I initially thought this could be accomplished by creating two separate legs extending from ground and connecting Analog to one and Digital to the other, but the still tie back to the same ground. So will this work or do I need to do something else?
...b. Which is Which –
......i. Analog – LEDs, LM317, LM334, 7805, ???
......ii. Digital – 74HCT05, LCC110, Timer, ???
Thank you,
BHinote
Last night I scribbled my version of the design. It's missing a few resistor values. The 74HCT05 is an Open Drain Device, so the R's driving LED's will be ~=(5-1.2)/20e-3 ohms. (5-1.2)10e-3 should work too.
You can even knock off a couple of parts by putting the LEDs in the opto relays in series. The opto relay is an LCC110. (digikey)
The R for the pull up can probably be just about anything from 1K to 10K.
The Lm334 resistor probably needs to be broken into fixed an variable parts or you can use your other current source. The simple LM334 source will be dependent somewhat on ambient temperature.
KISS