LPF Laser Pointer Company Database






Welcome to Laser Pointer Forums! If you are looking for a laser you may want to check out the database of laser pointer companies. The link will open in a new window for your convenience.

Green Laser Pointers Blue Lasers Pointers Red Laser Pointers
Yellow Laser Pointers Purple Laser Pointers Orange Laser Pointers
Laser Pointers by Power - 1 Watt+ Laser Pointers by Power - 500mW+ Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes


























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Newcomers > Welcome

LPF Database of Laser Pointer Companies




Reply
 
LinkBack Thread Tools Display Modes
Old 08-30-2011, 06:13 PM #1
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
cybhunter cybhunter is offline
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
Default Circuit design gone awry (don't know what happen)

A couple week ago I deiced to start building a laser pulse circuit. I ended up having a 555 chip in a 'one-shot mode' shoot a trigger into a NPN transistor to power a 1 watt 808nM diode

The goal was to

A: have a diode deliver 40 J/cm^2 in a pulse
B: have the pulse be variable up-to .25 seconds (for safety)
C: Use a 555 chip and 1 watt 808nM diode


the values I used for the timing circuit
(using: tau=ln(3)RC )
Resistance: 2,312 ohms (for .25 second pulse), variable
Capacitance: 100 microfarads, static
pull-up resistor (for pin 2), 10,000 ohms (momentary switched to ground)

Since I was using a 7805 (rated at 1 amp), I thought that by using a 6.6 ohm in-series with the laser should provide a stable 2.2 volt, .454 Amp supply (5volt- 2.0 volts= 3.0 volts= .454Amps*6.6ohms). The laser was attached to the collector of a TIP31 transistor with pin3 going to base

looking up the data sheet for the TIP, the hfe for ~.500 Amps Collector was around 100, so the base current would have to be 4.54mA. Assuming a voltage of 5 on pin 3, I calculated the resistance to 1,100 ohms.

trying to the fire the diode resulted in nothing happening. Checking the values, I was reading 4 volts across the diode leads when triggered and 180mA.

Out of frustration I ended up smashing the project box.

What I don't understand is
1) if the hfe is ~100 at ~500mA (collector), why was it only supplying 180mA (collector)?
2)the purpose of the resistor was to drop the voltage down to 2.0 volts and provide 454 mA, yet why was the potential 4 volts across the diode?

Attached is the schematic

Joe
Attached Thumbnails
Circuit design gone awry (don't know what happen)-laser.bmp  


cybhunter is offline   Reply With Quote








Old 08-30-2011, 11:08 PM #2
lasersbee's Avatar
Class 4 Laser
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
lasersbee lasersbee is offline
Class 4 Laser
lasersbee's Avatar
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

The first thing I would do is change the TIP31 for a HexFet.
The TIP31 will not fully turn 'ON'... a HexFet will...

When you supply 5volts directly to R2 will the output
voltage/current be high enough through the load???


Jerry
__________________

J.BAUER Electronics Home Page


LaserBee Laser Power Meter Products meet your needs
at affordable Prices:
See then all here on LPF

LaserBee Power Meter products ALWAYS in Stock

Available on eBay:Check availability here..

Search


This banner is available to and can be copied/used FREE by any LaserBee owner
lasersbee is offline   Reply With Quote
Old 08-30-2011, 11:17 PM #3
Flaminpyro's Avatar
Class 4 Laser
 
Join Date: May 2009
Location: West central Oregon
Posts: 5,448
Rep Power: 748
Flaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond repute
Flaminpyro Flaminpyro is online now
Class 4 Laser
Flaminpyro's Avatar
 
Join Date: May 2009
Location: West central Oregon
Posts: 5,448
Rep Power: 748
Flaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond reputeFlaminpyro has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

Shouldn't R3 connect back to the 12 volt supply and not the 5 volt supply
I don't think you will be able to draw the current you need to power the 808 if you
go through the 7805 regulator.

BTW what dose key=space mean ?
__________________
White Fusion Time Machine 445
473nm LRS-0473-KFM-00150-10 158.5mW Lab style
laser used in the making of the latest TRON movie

CNI PGL-III-C-589 125mW
520 in a SH-032
Viasho 532nm 500mW
CNI pen 532nm 84mW
The Violet Pip Squeek 45mW

_____________________________________
LOOKING FOR A HOST WITH PERFECT HEAT SINKING
order your C-88 Cu kit today !


Last edited by Flaminpyro; 08-30-2011 at 11:22 PM.
Flaminpyro is online now   Reply With Quote
Old 08-30-2011, 11:55 PM #4
lasersbee's Avatar
Class 4 Laser
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
lasersbee lasersbee is offline
Class 4 Laser
lasersbee's Avatar
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

Quote:
Originally Posted by Flaminpyro View Post
Shouldn't R3 connect back to the 12 volt supply and not the 5 volt supply
I don't think you will be able to draw the current you need to power the 808 if you
go through the 7805 regulator.

BTW what dose key=space mean ?
Good catch FP....
But with it tied to 12Volts then I m sure the TIP31
won't saturate with 5volts on the Base..


Jerry
__________________

J.BAUER Electronics Home Page


LaserBee Laser Power Meter Products meet your needs
at affordable Prices:
See then all here on LPF

LaserBee Power Meter products ALWAYS in Stock

Available on eBay:Check availability here..

Search


This banner is available to and can be copied/used FREE by any LaserBee owner

Last edited by lasersbee; 08-30-2011 at 11:56 PM. Reason: spelling errors
lasersbee is offline   Reply With Quote
Old 08-31-2011, 12:27 PM #5
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
cybhunter cybhunter is offline
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
Default Re: Circuit design gone awry (don't know what happen)

Quote:
Originally Posted by Flaminpyro View Post
Shouldn't R3 connect back to the 12 volt supply and not the 5 volt supply
I don't think you will be able to draw the current you need to power the 808 if you
go through the 7805 regulator.

BTW what dose key=space mean ?
That seems odd, considering the 808 is only taking 454mA, the 555 is at most taking 20mA, and the 7805 is rated up to 1A

the key=space just denotes that the space key triggers the push button in multisim

Getting back to the design, I ended up reconfiguring the leads so the current source bypasses the 7805, goes though 20.30 ohms: 12v(VCC)-2.0v(laser)-.7v(NPN drop)=9.3v --> 9.3=(20.39 ohms)*(454mA) and adjusted the pin3 resistance to 730 ohms

I couldn't find a hexfet component in Mutlisim so I left "Tip31" as the transistor

Also attached is the Oscilloscope view (with the 'space bar' push button) viewed across collector to emitter (Channel A) and base to emitter (Channel B)

Joe
Attached Thumbnails
Circuit design gone awry (don't know what happen)-laser-ii.jpg   Circuit design gone awry (don't know what happen)-oscilascope-view.bmp  
cybhunter is offline   Reply With Quote
Old 08-31-2011, 02:52 PM #6
Bluefan's Avatar
Class 3R Laser
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 61
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Bluefan Bluefan is offline
Class 3R Laser
Bluefan's Avatar
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 61
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

A transistor should work fine. You measured 4 volts across the diode? Sounds like you got the polarity of the diode wrong.
__________________
Highlights of my laser collection:
Big Sky Er:YAG - HP 8168D 1480-1570nm tunable laser source - Spectra Physics 3800 modelocked Nd:YAG - lots of IR diodes and bars - LPC-815 200mW 650nm - DL 6353TL 635nm 5mW - HP5501A stabilized HeNe - 2x Melles Griot 05-STP-910 stabilized HeNe - Spectra Physics 3500 Dye laser - REO 30536 543nm 2mW - Coherent DPY315-100 532nm 100mW SLM DPSS - Lexel 85 - 3x B&W tek 10mW 473nm - 445nm 3W Bluefan Sabre module - SF-AW210 150mW 405nm - DPSS inc 355nm 100mW Q-switched

Power meters:
Laser precision RkP-575 w/ RK-5710 - Ophir 10A-V2-SH - Ophir OEM 20C-A - HP 8152A w/ 2x 81521B - Coherent 212 - Anritsu ML93 w/ MA98A - 2x laser precision AM-400 - Leader LPM-8000

Bluefan is offline   Reply With Quote
Old 08-31-2011, 03:37 PM #7
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
cybhunter cybhunter is offline
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
Default Re: Circuit design gone awry (don't know what happen)

prior to hooking up the diode, I researched the pinout. To confirmed, I ran a continuity check (got 1.8xx), so I hooked it up that way. When the diode was attached to the circuit, the 180mA is way too much for leakage
cybhunter is offline   Reply With Quote
Old 08-31-2011, 10:50 PM #8
lasersbee's Avatar
Class 4 Laser
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
lasersbee lasersbee is offline
Class 4 Laser
lasersbee's Avatar
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

Looking at your new schematic....
I'm not sure why you even need the 5Volt regulator..
A 555 timer will work up to 16 volts...

http://www.national.com/ds/LM/LM555.pdf

BTW.. have you actually built this circuit or is it just
in a simulator ??


Jerry
__________________

J.BAUER Electronics Home Page


LaserBee Laser Power Meter Products meet your needs
at affordable Prices:
See then all here on LPF

LaserBee Power Meter products ALWAYS in Stock

Available on eBay:Check availability here..

Search


This banner is available to and can be copied/used FREE by any LaserBee owner

Last edited by lasersbee; 08-31-2011 at 10:51 PM. Reason: spelling errors
lasersbee is offline   Reply With Quote
Old 09-01-2011, 11:14 AM #9
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
cybhunter cybhunter is offline
Junior Member
 
Join Date: Aug 2011
Posts: 5
Rep Power: 0
cybhunter is on a distinguished road
Default Re: Circuit design gone awry (don't know what happen)

Its just out of habit to put in a voltage regulator in. Since I don't the parts I've only ran in simulation. Does anybody see any possible problem with the circuit (sans the 7805 and the tip31) before I create a parts list?
cybhunter is offline   Reply With Quote
Old 09-01-2011, 01:34 PM #10
lasersbee's Avatar
Class 4 Laser
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
lasersbee lasersbee is offline
Class 4 Laser
lasersbee's Avatar
 
Join Date: Sep 2008
Location: Quebec, Canada
Posts: 14,823
Rep Power: 477
lasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond reputelasersbee has a reputation beyond repute
Default Re: Circuit design gone awry (don't know what happen)

You may need to tweak R3 depending on the voltage
drop across the actual Laser Diode and U3....

Jerry
__________________

J.BAUER Electronics Home Page


LaserBee Laser Power Meter Products meet your needs
at affordable Prices:
See then all here on LPF

LaserBee Power Meter products ALWAYS in Stock

Available on eBay:Check availability here..

Search


This banner is available to and can be copied/used FREE by any LaserBee owner

Last edited by lasersbee; 09-01-2011 at 01:35 PM. Reason: Spelling errors
lasersbee is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Top 50 Laser Pointer Companies - Green Lasers Top 50 Laser Pointer Companies - Blue Lasers Top 50 Laser Pointer Companies - Red Lasers
Top 50 Laser Pointer Companies - Yellow Lasers Top 50 Laser Pointer Companies - Purple Lasers Top 50 Laser Pointer Companies - Orange Lasers
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes




Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 08:21 AM.


Powered by: vBulletin
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2016 Laser Pointer Forums, LLC