Could use some help please

Thread Starter

kurtruk

Joined Aug 26, 2012
140
Hello, as you may know I am new here and I have little knowledge of electronics as I am learning. Could you take a look at this schematic and see if you see anything wrong with it. I am especially concerned with the current. Do I have enough? What about all the Vccs of the ics?
Here are the links of the parts used

And Gates
http://www.digikey.com/product-detail/en/SN74AHC08N/296-4524-5-ND/375858

LEDhttp://www.digikey.com/product-detail/en/WP3A8GD/754-1217-ND/1747616

Transformer
http://www.digikey.com/product-detail/en/FS10-250/237-1031-ND/242476

Bridge Rectifier
http://www.digikey.com/product-detail/en/W01G/W01GDI-ND/278871

Voltage Regulator
http://www.digikey.com/product-detail/en/NCP553SQ30T1G/NCP553SQ30T1GOSCT-ND/3487600

Crystal Oscillator
http://www.digikey.com/product-detail/en/TC32N5I32K7680/CTX1184CT-ND/3511743

4520
http://www.digikey.com/product-detail/en/M74HC4520B1R/1026-M74HC4520B1R-CHP/2521285

Display
http://www.digikey.com/product-detail/en/LDD-HTC512RI/67-2098-5-ND/2239251

4511
http://www.digikey.com/product-detail/en/CD74HC4511E/296-14537-5-ND/555825

I think that is it except for more ordinary parts like resistors and capacitors
Any help at all would be appreciated please explain thoroughly as I am new to this. Note: any labels are what i think will happen not necessarily what will.
 

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Thread Starter

kurtruk

Joined Aug 26, 2012
140
i guess specifically my Qs about current is how much mA (current) should i apply to high inputs such as enable pins and how much current should i apply to Vcc of each Ic?
 

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Audioguru

Joined Dec 20, 2007
11,248
If the power supply for the CD4511 is only 3V then its voltage drop of 1V to 1.5V will not allow it to light LEDs that need 1.8V to 3.6V.
 

Thread Starter

kurtruk

Joined Aug 26, 2012
140
Ok for future reference how do I calculate that voltage drop and what about current on pins that need to be high and how much current should I suplly to Vcc pins of each ic
 

Audioguru

Joined Dec 20, 2007
11,248
Ok for future reference how do I calculate that voltage drop and what about current on pins that need to be high and how much current should I suplly to Vcc pins of each ic
The datasheet for the CD4511 shows its typical voltage drop vs output current. The max allowed output current is 25mA per output.
The datasheet for the LED display shows its range of forward voltage and its maximum allowed current per segment.

You do not supply current to the IC, instead you supply voltage. Then the IC takes as much current as it needs. If you do not use current-limiting resistors for each segment of the display (as shown in the datasheet for the CD4511) then the ICs and LEDs might blow up. Use Ohm's Law to calculate the voltage drop of the current-limiting resistors.
 

Thread Starter

kurtruk

Joined Aug 26, 2012
140
each of the resistors in between the 7 segment are 100 Ohm
does everything look okay for this the net running through the origin of each part would be the Vcc

Name Amount $ each $ total datasheet digikeylink
AC Chord
http://www.assmann.us/specs/AK500-OE-7-1-R.pdf http://www.digikey.com/product-detail/en/AK500-OE-7-1-R/AE10696-ND/2504538

Transfromer
http://system.netsuite.com/core/media/media.nl?id=5816&c=ACCT126831&h=7de295966eceb2cdb483&_xt=.pdf http://www.digikey.com/product-detail/en/VPP10-1000/237-1053-ND/242497

Bridge Recitifier
http://www.diodes.com/datasheets/ds21202.pdf http://www.digikey.com/product-detail/en/W01G/W01GDI-ND/278871

Capicator
http://www.chemi-con.co.jp/e/catalog/pdf/al-e/al-sepa-e/004-lead/al-ky-e-110701.pdf http://www.digikey.com/product-detail/en/EKY-100ELL102MJ16S/565-1504-ND/756020

Regulator http://media.digikey.com/pdf/Data Sheets/Toshiba PDFs/TA78xxSB.pdf http://www.digikey.com/product-detail/en/TA7805SB(TP,Q)/TA7805SB(TPQ)CT-ND/2264622

Resistor
http://industrial.panasonic.com/www-data/pdf/AOA0000/AOA0000CE28.pdf http://www.digikey.com/product-detail/en/ERD-S2TJ132V/P1.3KBACT-ND/503610

Crystal http://media.digikey.com/pdf/Data Sheets/CTS Corporation PDFs/Model TC32.pdf http://www.digikey.com/product-detail/en/TC32N5I32K7680/CTX1184CT-ND/3511743

Transistor
http://www.fairchildsemi.com/ds/2N/2N5551.pdf http://www.digikey.com/product-detail/en/2N5551YBU/2N5551YBU-ND/975303

4520 http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00002544.pdf http://www.digikey.com/product-detail/en/M74HC4520B1R/1026-M74HC4520B1R-CHP/2521285

4511
http://www.ti.com/lit/ds/symlink/cd4511b.pdf http://www.digikey.com/product-detail/en/CD4511BE/296-2072-5-ND/67341

LED http://www.us.kingbright.com/images/catalog/SPEC/WP3A8GD.pdf http://www.digikey.com/product-detail/en/WP3A8GD/754-1217-ND/1747616

AND
http://www.ti.com/lit/ds/symlink/sn74ahc08.pdf http://www.digikey.com/product-detail/en/SN74AHC08N/296-4524-5-ND/375858

Display http://media.digikey.com/pdf/Data Sheets/Lumex PDFs/QuasarBrite High Temp LED Displays.pdf http://www.digikey.com/product-detail/en/LDD-HTC512RI/67-2098-5-ND/2239251

Resistor 100 ohm
http://www.seielect.com/catalog/SEI-CF_CFM.pdf http://www.digikey.com/product-detail/en/CF14JT100R/CF14JT100RCT-ND/1830327
 

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SgtWookie

Joined Jul 17, 2007
22,230
Go back into Eagle, and click Erc. You'll get a lot of error messages, as you haven't provided nodes VDD and VSS for the 4000 series ICs, and you have multiple outputs tied together which is a no-no.
Use Erc early, and use it often. If you have any "Errors", you shouldn't try to create a PCB, or they won't be in sync - which is a real mess.
Use some of the symbols in Supply1.lbr or Supply2.lbr to add GND, VDD, VSS, etc to your schematic.
Alternatively, you could use the INVOKE command (looks like four AND gates on the left menu bar) and then click on each IC and select the "Request" entries (gate:p) to display the VDD/VSS/VCC/GND pins.

You should be using a 4000 series quad AND gate instead of the 74HC. A 4081 will do it for you.

The NPN transistor is wired as an emitter follower, but the collector is connected to what will be GND or VSS, and the emitter has no pull-down resistor. I'm not sure what you wanted to do there.

Your LEDs are connected backwards, and they do not have individual current limiting resistors.

You're limiting your power supply to 3v - why? 4000 series CMOS can use from 3v to 16v; some can go to 18v.

R1, R4, R5 and R6 will cause problems.
You need a fuse on the primary side of the transformer.

As far as schematic conventions; generally you have inputs on the left, and outputs towards the right. More positive voltages towards the top of the schematic, and more negative towards the bottom. For example, your ACPLUG should've been on the far left of the schematic, then a fuse, then the transformer, etc. Keeping your schematics adhering to conventions make them much easier for people to understand them quickly.
I prefer that people use a white background for schematics, as I find them easier to read that way.
 
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Thread Starter

kurtruk

Joined Aug 26, 2012
140
First off if I'm not using those output pins then I have to run a individual net to ground? Why can't they be tied together?

I guess I don't really understand resistors yet I'm trying to make it a switch because my crystal is limited to a max of 3mA but I thought I should have more current for the clk of the 4520s.

I don't understand how my LEDs are backwards isn't the electron flow coming out of the regulator and into the small side of the triangle like it supposed to?

As for the resistors why? I an thinking you are looking at the older schematic.
As for everything else thanks a better schematic is under creation.

Note: please tell why I can't do something otherwise I never learn knowledge I just learn facts (that's why i hate school they never tell you why ie why you can do what you do in math)
 

Thread Starter

kurtruk

Joined Aug 26, 2012
140
Ok for unused output pins do i just do nothing or what?

My crsytal osscilator is limited to 3mA; is my resistor right and then is the output big enough for the 4520s

If a resistor is unlabeled then it is 100 ohm

I don't understand how my LEDs are backwards isn't the electron flow coming out of the regulator and into the small side of the triangle like it supposed to?

SgtWookie said i needed i fuse: fuses are new to me. I put it on the 120V side of the transformer right? how big of a fuse do i need? Do i need two one for each wire running to the transformer?

Are there any other problems with the schematic?

also i know i practically this clock goes SS:MM:HH but it is just laid out that way on the schematic for easy reading.

Note it would be very helpful if you explained WHY.

I changed my and ic from TTL to CMOS here is the new data sheet:
http://www.digikey.com/product-detail/en/HCF4081M013TR/497-1140-1-ND/586140
 

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SgtWookie

Joined Jul 17, 2007
22,230
First off if I'm not using those output pins then I have to run a individual net to ground? Why can't they be tied together?
You're getting inputs and outputs confused. All CMOS INPUTS must have a current path to Vdd or Vss/GND, or you will have big problems. On the other hand, unused OUTPUTS should be left disconnected.

I guess I don't really understand resistors yet
I didn't understand them when I first started; nobody else did either.
I'm trying to make it a switch because my crystal is limited to a max of 3mA but I thought I should have more current for the clk of the 4520s.
The inputs of 4000 series CMOS ICs are like very small capacitors; nearly infinite resistance to Vdd and Vss/GND, and once charged or discharged it takes no current to keep them in that state. Your 3mA xtal clock should be able to work just fine as a system clock for the 4000 series CMOS. Were you using 74 or 74LS TTL, you would need to buffer your oscillator.

I don't understand how my LEDs are backwards isn't the electron flow coming out of the regulator and into the small side of the triangle like it supposed to?
You're getting electron flow and conventional current flow confused, which is very easy to do.
In this case, the regulator outputs +3v. Electron flow goes from more negative to more positive. Conventional current flow goes from more positive to more negative. We occasionally mention electron flow here, but we stick with conventional current flow to try to keep people from getting confused.

As for the resistors why? I an thinking you are looking at the older schematic.
I was looking at clock.sch that you had posted using Eagle 6.1.0. When you post a .sch or .brd file, you should also mention which version of Eagle you created the schematic or board with. A later version of Eagle can read files created by earlier versions, but once it's saved by a newer version, the older version cannot read it any longer.
As for everything else thanks a better schematic is under creation.
Good. :)

Note: please tell why I can't do something otherwise I never learn knowledge I just learn facts (that's why i hate school they never tell you why ie why you can do what you do in math)
I generally do try to explain why I recommend various things, because it may not be obvious to a newcomer - and learning things about electronics is one of the main reasons why the board exists. Unfortunately, I may not always have the time to explain things. You might notice it's been a good while between replies; I simply don't have as much time to spend on here as I used to.
 

SgtWookie

Joined Jul 17, 2007
22,230
Ok for unused output pins do i just do nothing or what?
Leave unused OUTPUT pins disconnected. Unused INPUTS must have a current path to Vdd or Vss/GND.

My crystal oscillator is limited to 3mA; is my resistor right and then is the output big enough for the 4520s
You did not specify the reference designator for the resistor in question. The reference designator is the letter/number combination next to the component; ie: R4, C2, Q5, T1, etc.

If a resistor is unlabeled then it is 100 ohm
You should always specify a value for resistors on schematics.
100 = 100 Ohms
1k = 1,000 Ohms
1M = 1,000,000 Ohms (note: in SPICE simulations, you need to use 1MEG instead of 1M)

I don't understand how my LEDs are backwards isn't the electron flow coming out of the regulator and into the small side of the triangle like it supposed to?
Think of the triangle as an arrow. The point of the arrow needs to go towards the more negative voltage.

SgtWookie said i needed i fuse: fuses are new to me. I put it on the 120V side of the transformer right?
Yes; this protects both the project and the human in case of a fault.
how big of a fuse do i need?
100mA to 500mA would be OK.
Do i need two one for each wire running to the transformer?
No, just one in the HOT wire. You don't want to fuse the neutral nor the GND wires. With a meter set on 200VAC or higher, you should measure less than 3v between Neutral and GND, and approximately 120v between the HOT wire and either Neutral and GND. [/QUOTE]

Are there any other problems with the schematic?
This is going to be an iterative process. You need to fix the existing problems first, then re-post your .sch file so we can take a look.

BTW, I prefer using the symbols in supply2.lbr over those in supply1.lbr.

also i know i practically this clock goes SS:MM:HH but it is just laid out that way on the schematic for easy reading.
Well, you have the schematic flip-flopped horizontally.
You really should have it the other way. It would be easier to understand.

I changed my and ic from TTL to CMOS here is the new data sheet:
http://www.digikey.com/product-detail/en/HCF4081M013TR/497-1140-1-ND/586140
OK, good.
 

Audioguru

Joined Dec 20, 2007
11,248
The part number for your displays is for common-cathode but your schematic shows CA pins (common-anode?) with the common pins connected to the positive supply.
The CD4511 drivers can drive only common-cathode displays.

The common pins of common-cathode displays should be connected to 0V.
 

Thread Starter

kurtruk

Joined Aug 26, 2012
140
This a list of what I changed

I added a fuse here is the datasheet/info:
fuse: http://www.digikey.com/product-detail/en/5MF 300-R/507-1258-ND/1009030
Fuse holder: http://www.digikey.com/product-detail/en/64900001039/WK0011-ND/245470

I changed my displays to common cathode (there were common anode just because i clicked on the wrong one)

I changed my CC of my displays from Vdd to Vss

I turned around my LEDs

I switched my schematic so it went HH:MM:SS

I changed my resistors R1-R46 to 500 Ohms

I changed R48 to 1800 Ohms

I think that is it.

I posted both a .sch and a .png (.sch is in the zipped folder because it was just to big to upload it)

I'm not 100% sure my resistor values are correct.

Thanks for all the help without you I would just try to build it and get very frustrated.
 

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Audioguru

Joined Dec 20, 2007
11,248
Using the very low supply voltage of 5V and the very high value 500 ohm resistors to limit the current in the displays to about only 4mA then the displays will look very dim.
 

Audioguru

Joined Dec 20, 2007
11,248
Ok so I know V=IR so why wouldn't 5=x500 so you divide both side by 500 and get 0.01 or 10mA what am I missing?
The 5V is not across the resistor producing 10mA.
The 5V is divided across the LED in the display (maybe 2.0V or more for a green display) and 1V or more is lost in the output of the CD4511 so only 2V or less is across the 500 ohm resistor producing only 4mA or less.

Your schematic is as big as my neighbourhood because its parts are too far apart.
 
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