Hi everyone!
Back again and sorry I didn't do the Schmitt Trigger simulation yet but I had a problem with my spare time and with LTspice too.
Posted by: shafri
HAHA! thats more like it. congratulation! welcome to EEVBlog for anyone interested in electronic design... for makers and "hackers" haha! Grin
next move? buy an oscilloscope and multimeter! if you still not own one, it will display some reality, not the simulated one.
and when you go advance, you can start looking for function generator, spectrum analyzer etc etc all those fancy gadgetries!
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
Well, since i can't afford to buy an oscilloscope right now, I'll use the ones i have available xD
First of all, here is a picture of the LM741 oscillator connected to an oscilloscope. It was working at 250 Hz with a 100 uF capacitor . I made a video of it working at around 2 KHz using a 10 uF capacitor which link is:
Posted by: Hero999
Good, I'm glad you've got it working.
Please note that the CMOS IC must be 74C14, if you use the 74HC14 you'll need to add a current limiting resistor for the LED and use a 3V to 6V supply.
Thank you Hero999!
Now for the Schmitt Trigger, I couldn't quite find the proper model in LTSpice to do as Mr. Hero999 said. I'll still search if there are any libraries with it.
Posted by: KTP
Wow, nice video...even has a catchy soundtrack Grin
All of Hero999's suggestions are really the better way to do this, but when I made the circuit I wanted to only use what we were given in our tiny kit of lab parts for the intro EE class so that everyone else in the class could make the same blinky led with their parts. The only semiconductor we had in the kit was the lowly 741 op-amp (ok, it was a really intro EE class...I made a 99.5 average Wink ). Too bad nobody else in the class seemed interested in doing the circuit or anything else other than the minimum homework problems to prepare for the tests. I found a similar attitude in the mosfet class I just took. Ah well, I think I had more fun than they did.
Good job, keep at it! After you get comfortable making oscillators we can try driving a mosfet with it that is hooked up to an inductor with a catch diode and capacitor filter after. This would be the start of a very crude open loop unregulated switching boost converter, which could turn the 9 volt battery voltage into 24 volts or even higher (for small loads). Watch Dave's video on regulators when you get a chance.
Yes, it happens. Some people just don't get a kick out of electronics right away. I think some start to have fun after a while.
Thanks! I'll still keep testing and trying new ones, see what I can get. Right now i want to test the Schmitt trigger Mr. Hero999 has suggested. Then I want to compare them. So for now, until I can't do the Schmitt one, I'll make this one on a PCB, so i can use it later easily for comparison.
P.S.: I know I know, my multimeter is a piece of $#%&/#/, but oh well, I didn't see the multimeter review videos before I bought it (I bought it around 6 months ago). It was around 30€, it was the best in the store I bought it, the next above it was a Fluke which costed +/- 300€
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
but yes, if it was now, I would prefer to buy a BK Precision BK2709B which really got me on the video Mr. Dave just did about 100$ multi meters.
Bye for now everyone, I shall be back with the "war on" Schmitt Trigger
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
!