[Crystal Earphone Amplifier]

This simple, one-transistor amplifier provides a voltage gain over 1000 (60 dB) for driving a high impedance ceramic (crystal) earphone. The high gain is achieved by replacing the traditional collector resistor with an unusual constant-current diode that supplies 1/2 mA yet exhibits a very high resistance to the audio. This amplifier will give excellent battery life, drawing only 500 uA.

Below is a typical application using it with the first crystal radio circuit. The amplifier provides good volume with a modest antenna. You may want a volume control as with the TL431 project!

Or use the Crystal Radio RF Amplifier directly above for even more sensitivity with less than 2 mA current drain.

[PCB manufacturing sites - work in progress]

4. http://expresspcb.com/

The Free PCB software is a snap to learn and use. For the first time, designing circuit boards is simple for the beginner and efficient for the professional. 

[PCB manufacturing sites - work in progress]

I think I can add more comparing information here for reference.

1. PCBWay pcb prototype company

A manufacturer that specialized in PCB industry. $5 cut for the first order. If you need long-term purchasing, they provide more coupons. More customization choices vs itead. Delivery time with DHL or HongKong post is pretty satisfying. Shipping fee is much cheaper. According to my experience,you can also get the free universal boards. Placing an order is simple. Type in the specification and upload the files, waiting for auditing! Then dont worry, there's someone contacting you if there's something wrong with the file.

 

2. pcbgeek

PCBGEEK.COM is specialized in 1-22 layers boards in Prototype,Small & middle volume PCB with fast speed according to clients' requirement. They also can do Blind/Buried Hole Board, High Tg Thick Copper PCB, Mix- Material Multilayer PCB, Flexi-rigid Board, Flexible Board, Metal Core Board, Aluminum Board, Thick gold plated board, Solder Stencil and so on. 

 

.......

 

I am not familiar with following houses. Welcome your discussion!

3.San Francisco Circuits

San Francisco Circuits is a one stop solution for PCB services - PCB manufacturing & assembly. 
With the resources of a strong PCB manufacturer's network and the expertise, San Francisco Circuits provides you with a unique one stop solution to all your PCB needs: PCB design to PCB manufacturing, fabrication & assembly. 

[PCB manufacturing sites - work in progress]

This is a question always been asked so I try to make this list to cover as many pcb manufacturers as I can.

This is a listing of websites making PCBs and  also may including PCBAs. I will try to update the infomation now and then.

http://www.pcbway.com/ -$5!!!

http://www.pcbgeek.com/

http://www.sfcircuits.com

http://expresspcb.com/

http://www.apcircuits.com/

http://www.10pcb.com/

http://www.goldphoenixpcb.com/

http://batchpcb.com/index.php/Products

http://www.pad2pad.com/index.html

http://www.pcbcart.com./

http://www.4pcb.com/

http://www.pcbfinpo.com/

http://www.sunstone.com/

http://www.pmsnewzealand.com/

http://www.ezpcb.com/ezpcbweb3/index.php

http://dorkbotpdx.org/wiki/pcb_order

http://pcbconnect.com/index.html

http://www.screamingcircuits.com/Order/

http://www.pcborder.com/site_new/default.asp

http://www.custompcb.com/

http://www.multi-circuit-boards.eu/?gclid=CK20v5fFga4CFYZN3godg1in6Q

http://iteadstudio.com/store/index.php?cPath=19_20

https://www.itead.cc/open-pcb/pcb-prototyping.html

http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html?cPath=185

http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html?p=2&price=-100 - $0.2 !!!

https://ecommerce.pcbfabexpress.com/

http://www.goldphoenixpcb.com/

http://oshpark.com

https://www.protoexpress.com/ - SierraCircuits

http://www.4pcbassembly.com/

http://www.mitchelectronics.co.uk/

http://www.customcircuitboards.com/

http://dirtypcbs.com/

http://www.elecrow.com/special-offer-for-2-layer-1010cm-max-green-pcb-510pcs-p-761.html

http://pcbshopper.com/

http://smart-prototyping.com/PCB-Prototyping.html

http://www.technotronix.us/

http://www.pcbunlimited.com/

http://store3.sure-electronics.com/

The list is not in any priority. I've never ordered board from any houses. I've just made board with the first two entries.

This is a "work in progress". New board houses may be added, along with some comments. 

[Cheap OLED Displays and Arduino]

Project with Arduino to share...

I have tried to make a similar one befire, but it failed. Hope this article helps you like it helps me.

[PCB manufactureres]

For PCB prototype and copy pcb, I strongly recommend pcbway(http://www.pcbway.com/q  ).I have bought 5 pcs single sided pcbs from them with $17. As there's $5 discount, the total price is $13. The boards are pretty good with high quality. I revceived them within 5 days.

If you have boards, PCBWay also can design diagram and gerber files and Bom lists for you.