I have tested all the 7809 mosfets individually, on bread board, and then in soldered position, but without the CMOS chips mounted (i.e no load on the 7809's, and they all give out within a fraction of a voltage of each other, 9V. I'll have to check again what they are doing once loaded with the CMOS chips, but again, i must stress to remind people that i've got two chips working on one side. If i remove the working chips, and put two other (tested ok, but known not to work on my circuit) chips in their place, then these DON'T work....under exactly the same circumstances as the first working two. I would have thought that a couple of CMOS ~NAND's and transistors and resistors are hardly going to affect the supplied voltage by much....!?

I've also tested my circuit, on breadboard, using 12V without mosfets, and the circuit was good. I'm only introducing the mosfets for stability of working voltage because a vehicles operating voltage can swing from about 11V to about 14V, not even including any transients according to switching on and off other systems on the vehicle.

The purpose of the 7809's is for stabilised clean power for the chips. I want to design something to go into an automotive environment. Some people are giving my suggestions of other, more automotive environment friendly (reliable) devices to use, and i've taken note of this, and may still pursue, but right now, i've got 90% of the way there already in the direction i've taken already, so would like to exhaust this approach first before i potentially change direction after the new year.

 

I have tested all the 7809 mosfets individually, on bread board, and then in soldered position, but without the CMOS chips mounted (i.e no load on the 7809's, and they all give out within a fraction of a voltage of each other, 9V. I'll have to check again what they are doing once loaded with the CMOS chips, but again, i must stress to remind people that i've got two chips working on one side. If i remove the working chips, and put two other (tested ok, but known not to work on my circuit) chips in their place, then these DON'T work....under exactly the same circumstances as the first working two. I would have thought that a couple of CMOS ~NAND's and transistors and resistors are hardly going to affect the supplied voltage by much....!?

I've also tested my circuit, on breadboard, using 12V without mosfets, and the circuit was good. I'm only introducing the mosfets for stability of working voltage because a vehicles operating voltage can swing from about 11V to about 14V, not even including any transients according to switching on and off other systems on the vehicle.

The purpose of the 7809's is for stabilised clean power for the chips. I want to design something to go into an automotive environment. Some people are giving my suggestions of other, more automotive environment friendly (reliable) devices to use, and i've taken note of this, and may still pursue, but right now, i've got 90% of the way there already in the direction i've taken already, so would like to exhaust this approach first before i potentially change direction after the new year.

That "fraction of a volt" may be important. The 7809 voltage regulators may be the reason for your problem. You can't apply a higher voltage to the input than the chip is powered by. A fraction of a volt can be a problem.
A close analysis of the chips that failed, please. Specifically what was it that failed? An output or an input? Specifically where was that input or output connected?

 

the datasheet says +/- 0.5V of VDD, which they are well within.

 

the datasheet says +/- 0.5V of VDD, which they are well within.

Thanks, that answers that question. We are back to mysterious failures then. I've been playing with CMOS stuff since it came out with and without an anti-static station. I've never killed one yet. Are we back to a close analysis of where and how these died?

 

the datasheet says +/- 0.5V of VDD, which they are well within.

I gues those numbers come from Absolute maximum rartings, not Reccomended operating conditions.

 

I've got another 18 on order from two different eBay sellers. They're due for delivery to my house either today or tomorrow (Xmas post dependent of course), so we'll see what results from yet another batch of chips. 21oo23 already proven to be useless. I'll pay particular attention to not getting the two sources mixed up this time and feed people the results...

 

Hi again..

um...so...your calling the 7809 a mosfet but from what I can tell its a voltage regulator.

The reason I asked if you tried your circuit without the voltage regulators was to very the 4011s are bad. The regulators need at least 5ma current draw to regulate properly and your using them in a way that's s little odd. You should really just use one to regulate the voltage for the whole circuit.

If your 4011 chips test ok on the bench..then there is something likely wrong with the circuit. The chips that are working might just happen to be more tolerant to what ever is causing the circuit to fail.

 

Is mosfet not the correct name for a 7809? I thought it was. Sorry.

I can't use just one 7809 because each input would also be a 12v feed into an input, so I put a 7809 into the VDD circuit AND each of the inputs to the logic.

 

A 7809 is called a three-terminal regulator. It is the back end of a small power supply cooked down to a single component. Inside it has a voltage reference, error amplifier, power transistor, thermal monitor, and current monitor. In your circuit you are using it as an input signal conditioner. Not a bad idea, and ok if you have a few laying around, but relatively expensive compared to more traditional methods. As you describe more and more of what you have done, I think the only answer is that you got a bunch of bad chips. Compared to ebay, traditional distributors are more expensive and more reliable. Life is choice.

ak

 

Is mosfet not the correct name for a 7809? I thought it was. Sorry.

I can't use just one 7809 because each input would also be a 12v feed into an input, so I put a 7809 into the VDD circuit AND each of the inputs to the logic.

Just to make sure you don't have a power sequence or overshoot problem, try powering the ICs from the 12 volts and see if your good bad ICs turn good.

 

Yes...just as a test....try the circuit without the regulators.

Also....keep in mind the 7809 has a drop out voltage of 2v.

 

I've just tested a newly arrived 18 chips. Not one worked.

I can't even type right now, I'm so angry!

This is how they arrived from "moorland supplies" on eBay.

 

My circuit was prototyped without the 7809's.

 

I've just tested a newly arrived 18 chips. Not one worked.

I can't even type right now, I'm so angry!

This is how they arrived from "moorland supplies" on eBay.

Looks ok to me. Anti-static foam and bag.
What do they do?

 

Hello,

What are the partnumbers of the chips in the image?

Bertus

 

The clue is in the name of the thread.

I've been in touch with the eBay guy.

He sounds legitimately sorry and shocked. He's now questioning his stock in total (I wonder why!?)

He says he's gonna send me another 36 to cover what I've bought from him so far. That's gonna be me now until after the festive period. Can't do anything else until I get some good chips.

 

Max Vf for the LUW-W5AP LED is 4.3v, applying 12v is probably too much.

Max Ic for BC847C, Q3 is 200ma, the V/I curve for the LUW-W5AP is 1.4 Amps at max Vf.

There is no current limiting resistor at the base of the BC847C transistor, and is probably taking out the 4011.

 

There is no current limiting resistor at the base of the BC847C transistor, and is probably taking out the 4011.

The circuit in post #22 is contrived (post #48).

 

Contrived?

Why can't people post real schematics! This is just wrong! What's the point?

Sorry, but I tend to take thing much too literally.

 

My circuit was prototyped without the 7809's.

And the circuit worked when they all ran from the same +12 V?