Ok I'm in the home stretch here, just a few more exams to go before I graduate. I'm onto a hands on wiring/components parts part of the course. You have a briefcase size piece of equipment to wire parts on.

I'm supposed to wire a IC358 dual op-amp with resistors. Three 1 K-ohm resistors and 100 K-ohm resistor with 10 microfarad capacitor too. Its supposed to make one of the LED's blink, but mine is on solid instead of blinking. I need it to blink because that is what its supposed to do, and because its a question too. They want me to record how many times the LED blinks in 60 seconds. I believe it will be 30 times, but thats just a guess. I know this hard to diagnose from where you are, but any suggestions? Thanks for any help, again.

 

Well, supplying a schematic would be a good place to start

 

Hello,

The following PDF's from TI will give you a lot of information on the use of opamps:
sloa011Understanding Operational Amplifier Specifications.pdf
sloa058 A Single-Supply Op-Amp Circuit Collection.pdf
sboa092a_handbook_of_operational_amplifier_applica tions.pdf

Think of an integrator and a schmidt trigger.
A hysteristic oscillator is also possible.

Bertus

 

I got it to blink, I finally got it. I was using the wrong resistor. Resistors are really pains in the butts to see. I have great eye sight too, lasik eye surgery a few years ago. Yellow in very hard to see on resistors. Well I got it to blink, and its around 3o blinks per go seconds. Fun doing trouble shooting on a circuit I out together. Stayed tuned guy I have LOTS, I mean LOTS more experiments to do.
Oh by the way the schematics are in my books, how can I post them on here? I'm not the most computer savvy guy mind you, I do what I can. Thanks for the help.

 

Hello,

If you want to post the schematic from a book, you can scan it on a flatbed scanner or take a picture with a digital camera.
In the FAQ is given how to attach it:
Attachments and Images

The popup will give you the maximum size you can use.

Bertus

 

Thanks bertus, I will give that a shot if I run into more trouble. It certainly was fun troubleshooting my own work. Finding out what was wrong, then fixing it.
I'm trying to email every electronics tech employer in my area to see if they need or will hire a junior tech that will graduate soon. No bites at all yet. Should I expect someone to take a chance on a student ET for a junior technician job or its futile till I actually graduate with a diploma? Thanks again for the help guys.

 

You get what you pay for.
Cheap Asian resistors use cheap paint for the colour stripes. Yellow, brown and red look almost the same. Green and blue look almost the same.

I got cataracts in my eyes so I had the foggy and yellowed lenses replaced. Now every colour is vivid and different (your old lenses probably make everything look yellowed).

 

When in doubt ... break out the ohm meter. My eyesight is going bad ... as reading chips are blurry (I use reader glasses now), but I will breakout the extra magnifier if necessary and whatever meter I might need to verify components.

 

Thank you Joejester. Even with the magnifying glass the colors seems to be faint. The ohm meter suggestion is a good idea, thanks.

 

You get what you pay for.
Cheap Asian resistors use cheap paint for the colour stripes.

We used to have a lab rat named Fran who frequented electronics swap meets, had tons of resistors. I remember I needed some to build up some demo borads real fast, put them in: we always defluxed the boards using acetone. The stuff melted away all the color stripes on the resistors. Not a trace of color left, just bare naked resistors.

They worked though.....

 

When in doubt ... break out the ohm meter.

Funny how many resistors I find "out of spec" when I do that. I have a set of .01% tolerance resistors to keep my meters calibrated, but a lot of 5% resistors I check are out of tolerance spec.

 

Funny how many resistors I find "out of spec" when I do that. I have a set of .01% tolerance resistors to keep my meters calibrated, but a lot of 5% resistors I check are out of tolerance spec.

take them back. but be sure your meter has a dated calibration sticker on it.

 

I like the "resistors" that have a single black band. Their resistance is always extremely accurate.

 

I like the "resistors" that have a single black band. Their resistance is always extremely accurate.

I'm sure there will be a lawyer looking to make a name for themselves will sue for false advertising.