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a BIG thanks to all. I am sure I will be back with more questions once I get a chance to build again. For, the Wife needs her new Mother's day dishwasher installed.
Eric's setup powers both the LM358 and the LM3914 with a constant voltage that I will be providing with an LM317 to deal with the fluctuating (10.8-13.8V) supplied by the motorcycle. What about altering the frequency?
hi goaticus,
It is common practice on Forums, when the project is going smoothly over a few days and is coming to a successful conclusion, someone else who has not taken the trouble to the read the previous posts on the thread, start making suggestions which are out context of whats been discussed earlier.
If I see a thread thats making progress between an OP and a 'helper,' I try not to muddy the waters by posting my four cents worth.
Lets know when the dishwasher is operational.
I bet someone starts posting comments on how not to install a dishwasher.!
I do think it's off putting when people respond making unhelpful comments that put someone else's contribution down; seriously if you can't post anything helpful then don't bother.
I understand both sides. I am a moderator on my motorcylcle forum. Sometimes you don't check a post out right away and then you notice that the post is persisting and you decide to finally check it out. I find I will get bored trying to catch up and skip ahead sometimes missing something important that was buried in the cheeky comments. On the other hand it can be a bit annoying when someone goes straight to the last post, bypasses everything, and says something that has already been mentioned several times. None the less, I hope neither of you shy away when I inevitably return with questions.
I picked up a dual op amp at the Shack yesterday (not listed as an LM358, bit is a TI part with the same pin layout) and got started last night. No building tonight though. Too wrecked from ongoing dishwasher installation...
The part is a TI part from radio shack, the TL082 Dual BiFET OP Amp. The little diagram on the back is identical to the one below for the LM358. I am going to have to make a digikey order anyways, though. So, eventually I will get an LM358. But, for now, I hope the TL082 will work. It's funny, but when you go the the RS site, and look at the TL082, it shows a pic on a National Sem. part instead of the TI part.
The part is a TI part from radio shack, the TL082 Dual BiFET OP Amp. The little diagram on the back is identical to the one below for the LM358. I am going to have to make a digikey order anyways, though. So, eventually I will get an LM358. But, for now, I hope the TL082 will work. It's funny, but when you go the the RS site, and look at the TL082, it shows a pic on a National Sem. part instead of the TI part.
Hero, could you give me some more info on the transistor in this circuit. I don't know enough to order the right one and am putting together a digikey order.
The transistor isn't critical any small PNP transistor will do, the BC328, PN2907, BC557 etc. there's a good chance, you've already got a transistor that'll work in your junk box.
That spice file gives me a load of errors because I don't have the models.
Here's my version which doesn't use and fancy models. It's probably not so accurate as yours but it saves the trouble of having to download lots of models.
I wish LTSpice featured an embed model option, it'd make posting simulations much easier.
Well, I have it all built on my proto board and hooked up to a 9v (and 12v for confirmation) and it seems that the 7808 isn't doing anything to reduce the voltage. I bought THIS one from ST. I think I have it set up correctly. Looking at the side with the labeling, pins down, from left to right 1-2-3; I hooked pin1 to the power supply, pin2 to ground, and pin3 as the 8v out. I ran both capacitors connecting pins 1 and 2. Did I not set it up correctly? Is it not functioning correctly?
Is your power supply DC?
Do you have short leads going to the regulator?
You need at least 11v to be sure to get 8v out.
What output voltage are you getting?
Do you have a load on the output?
Do you have 100n up close to the regulator?
Are you sure it is 7808?
Is your power supply DC? Yes
Do you have short leads going to the regulator? Yes
You need at least 11v to be sure to get 8v out. Check. I used a freshly charged motorcycle battery 13V+ to confirm
What output voltage are you getting? The same as (or extremely close to) the input
Do you have a load on the output? Yes, it is connected to the rest of the circuit which is funtional
Do you have 100n up close to the regulator? Yes (assuming I didn't botch the conversion... 100nF = 0.1uF....?)
Are you sure it is 7808? Yes, it says L7808CV
Did you try it previously?
Did you put it around the wrong way at any time?
Did you disconnect the supply when the load was still connected?
Always buy three of anything, as things like this always happen.
Do the capacitors sound like they are correct? When I looked up the datasheet, it showed 2 being used also, but one went from Vin to ground and the other went from Vout to ground. As I stated previously, I have both going from Vin to ground (pin1 to pin2).
Do the capacitors sound like they are correct? When I looked up the datasheet, it showed 2 being used also, but one went from Vin to ground and the other went from Vout to ground. As I stated previously, I have both going from Vin to ground (pin1 to pin2).
hi,
Usually there is a 100nF on the input side and output side of the 7808 Vreg, as close to the reg as possible.
If you have a diagram showing the latest circuit, post it and will check it out.
Your description on how the 7808 is connected sounds OK.
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