Yeah I got my build-in to my DC/DC power supply.
Plus I cannot buy for Amazon as it cost to much to delivery to OZ.

 

How long before Wendy check this circuit?

 

Eric,
I see you use this web site as well below!
Did you read this? Regarding NE555 timer for LTspice: http://www.electro-tech-online.com/threads/555-transistor-level-ltspice-model.142957/

 

Hi Andy,
Yes read that link OK.
Do you have a bread board that you could build just the SMPS/555 part of W's circuit.
You could then use a resistive dummy load to test it to approx 150mA and then scope the waveform across the load to determine the voltage swing.
In series with dummy load add a 1N4001 diode, this will give a very rough guide in the way the final LED array will perform.

E

 

Breadboard No.
Resistive dummy load No.
Scope No.
I can give you the manufacturer of 555 would that help?
Sorry.

 

I don't see why you want to give me the manufacturer of the 555.?

The problem is not with the 555 it is with the very poor regulation of the design of the 555 switcher for driving the LED's in your project.
The LTSpice simulation shows that the LED current would be much higher than the specified LED limit.

I would prefer not modifying W's circuit.
E

 

WELL IT LOOK LIKE SHE NOT ANSWER TOO THIS THREAD, SO PLEASE DO Eric? I'm fed up waiting.
Andrew

 

hi Andy,
This is one option, change the LED array layout to suit the high Vout, this will lower the LED current.

You may need to adjust the {rs} resistor value a little to optimise the current and brightness of the LED's [ note the right side LED chain has a 240R resistor.]

The FET can be any N MOSFET with a Id current rating over say 1 or 2 amps.
Let me know the FET type you have and I will check the spec.

E

 

Excellent Eric, the FET I need to purchase yet, Yes I will forward the spec.
So we have an output of 36 volts, 10.9mA per led, Yes I note the RS value for adjustment of led and the last one is 240 ohms.
Any chance of forwarding to me this LTSpice test of this circuit? as I like to learn? just upload to a cloud Eg: google drive, or attachment.
Andy

 

This is the LTSpice sim asc file, attached.

I would suggest you join the free Yahoo/LTS user group, lots of models etc.
https://groups.yahoo.com/neo/groups/LTspice
E

 

Have done.
Thanks, again.
Where the TLC555 timers? there missing?

 

hi,
Unzip the attached zip.

Place the TLC555.asy file in the LTspice\lib\sym folder.

Place the TLC555.asc files in the LTspice\MyWork\555 folder
[you will have to create the MyWork\555 folders or use folder names of your own choice]

Place the TLC555_mod.txt file in the LTspice\MyWork\555 folder

Place the timers.lib in the LTspice\lib folder.

You should now be able to run LEDsmsp1.asc

I would suggest you consider creating a folder in the LTSpice main folder for all your work [mine is MyWork] also sub folders under MyWork, use sub folder names that are easy to recall

Shout if you have a problem.
E

 

Thanks will do.

 

Would this FET do: http://www.ebay.com.au/itm/n-Channe...8BDS-T1-GE3-/111707727376?hash=item1a024ca610

http://www.farnell.com/datasheets/1911751.pdf

• Mosfet, n Ch, 60V, 2.3A, Sot23-3
• Transistor Polarity: n Channel
• Continuous Drain Current Id: 2.3A
• Drain Source Voltage Vds: 60V
• On Resistance Rds(On): 130Mohm
• Rds(On) Test Voltage Vgs: 10V
• Threshold Voltage Vgs: 3V
• Power Dissipation Pd: 1.09W
• Transistor Case Style: Sot-23
• No. of Pins: 3
• Operating Temperature Max: 150C
• Msl: Msl 1 - Unlimited
• Current Id Max: 1.9A
• Operating Temperature Min: -55C
• Operating Temperature Range: -55C To + 150C
• Packaging: Cut Tape
• Voltage Vgs Max: 20V

Manufacturer: VISHAY SILICONIX
Manufacturers Part No: SI2308BDS-T1-GE3
FastFind Code: YXH2AAAD

 

hi.
That FET looks OK, I tried the nearest LTS FET Si2318CDS in the Sin OK.
E

 

Quick question I buy 5 cheap LDR's from China, what I thought where 10 M ohms, they are all over the place in ohms.
1./ Light resistance 0.9K Dark resistance 6.5K
2./ Light resistance 1.4K Dark resistance 12.7K
3./ Light resistance 0.8K Dark resistance 6.4K
4./ Light resistance 0.9K Dark resistance 6.5K
5./ Light resistance 0.75K Dark resistance 9.7K

Or should cut my losses and go a buy a 10M ohm LDR?
Or I need to add more resistor to the 555 timer circuit?

 

hi A45,
I would suggest using the Chinese LDR's, just change the series resistor.
The biggest change looks like LDR #2 or #5, I will run them in simulation and post what I find suitable. OK
E

 

Thanks Eric

 

Hi Andy,
Look at this option.
Shows the 1st 555 only, for clarity.
The 5k pot will give Light/Dark OK for the #2 LDR.
E

EDIT:
Note the tripping voltage for the 555 Trig, is ~8v with a 12v Supply, ie: [2/3] * Vsup

 

Hi Eric,
That No good, as the circuit has a 100K variable resistor and 39K ohm please look at the circuit?