LT Spice Simulator

Linear Technology has a great Spice simulator available as a free download. Enter the circuit using the schematic editor, specify the stimulus, run the simulation and then plot the results.

Attached is an example circuit and the output plot. The circuit is a simple log converter.

Yahoo support group (~10K members): LTspice

Schematic/PCB Tools

More collected wisdom from SDIY, summarized by platform, capability, cost and support. Another useful metric would be library depth, but that's too much work for today. Presented in alphabetical order:

DipTrace

• Windows commercial product
• Full suite of tools
• 250 pin limited freeware version to $695 full, non-profit version $125
• Yahoo group (~1000 members) : diptr

Eagle

• Linux, Mac, Windows commercial product
• Full suite of tools
• Limited freeware, Standard $398, Pro $798, autorouter additional
• Official News groups for support: eagle.support.eng
• Yahoo group (~800 members): eaglecad
  

FreePCB

• PCB Layout only
  
• Windows
• Open Source
• Yahoo Group (~450 members): FreePCB
  

gEDA

• Full suite of tools
  
• Linux
• Open Source
• Wiki
  

Kicad

• Full suite of tools: Schematic Editor, PCB Layout, Gerber Viewer
• Multi-platform Linux, Windows, Mac(?)
  
• Open Source
• Multi-language support
  
• Yahoo group (~1650 members): kicad-users
• Sourceforge Wiki
  

Osmond PCB

• PCB Layout only
• Mac OS-X
• Yahoo group (~350 members): osmondpcb
  

Rimu Schematic and PCB

• Windows commercial product
• Schematic Editor full version $149
• PCB $72.50
• No apparent forum or users group
  

TinyCad Schematic

• Schematic Editor
• Opensource
• Windows only
• Yahoo group (~1850 members): tinycad
  

SMT Prototyping Board Suppliers

Collected wisdom from sdiy:

One Pas has a fairly wide selection, combined SMT and thru-hole, endorsed by Forrest Mims. Also sells pcb drills. ebay store

Bellin Dynamic Systems about $45 bucks for a break apart board. Sold by JameCo, Mouser

ePBoard SMT to DIP adapters, online ordering

etteam "surf boards" at FuturLec, cheapest low quantity option

SchmartBoard available at JameCo, Fry's

Karate Lessons

Spotted July 2007. Turns out there are more.

transistor array availability

National:

• LM3046, 5xNPN, datasheet, 1K/0.39
• LM394 2xNPN, datasheet,

Intersil:

• CA3083 5xNPN, datasheet
• CA3054 dual diff amp, datasheet
• HFA3046 5xNPN
• HFA3096 3xNPN, 2xPNP

THAT Corp:

• 300 Series, datasheet, 1K/3.00
• 300 - 4xNPN
• 320 - 4xPNP
• 340 - 2xNPN, 2xPNP

Available in small quantites: http://www.ka-electronics.com/that300/that300.htm

Analog Devices:

• MAT01, 2xNPN 100uV datasheet
• MAT02, 2xNPN 50uV datasheet
• MAT03, 2xPNP 100uV datasheet
• MAT04, 4xNPN 200uV datasheet
• SSM2210, 2xNPN 200uV datasheet
• SSM2220, 2xPNP 200uV datasheet

Fairchild Semi:

• FFB3904, 2x3904 NPN datasheet
• FFB3906, 2x3906 PNP datasheet
• see also similar 2222A and 2907 parts
  

• MMPQ2222A, 4x2222A NPN datasheet
  
• MMPQ2907, 4x2907 PNP datasheet
  
• MMPQ3904, 4x3904 NPN same datasheet as FFB3904
  
• MMPQ3906, 4x3906 PNP same datasheet as FFB3906
• MMPQ670, 2x3904, 2x3906 datasheet