Here's a reprise of the post with Bruce's schematic. I managed to send it for him a bit later. Unfortunately the archives do not do attachments. If you're subscribed, Ted, you should be able to pick up the attached .gif file. If not, let me know and I'll forward it to you separately.
Be well, Mike D. PS> High voltages here, folks! Don't mess with projects like this if you don't have a *thorough* grounding in electronics. (No pun intended.) ------- Forwarded message follows ------- Date forwarded: Wed, 15 Oct 2003 14:10:13 -0700 From: "M. G. Devour" <[email protected]> To: "Silver List" <[email protected]> Copies to: <[email protected]> Date sent: Wed, 15 Oct 2003 17:09:19 -0400 Forwarded by: [email protected] Send reply to: [email protected] Subject: CS>160 VDC current regulator Bruce has been struggling to send the following file as a Word document. I've succeeded in shrinking the graphic and reformatting it as HTML so it will be small enough to fit through the list server. MS Word is *NOT* and efficient file format. Hope this works! Mike D. -------- Begin forwarded message 160 Volt Constant Current CS Generator updated 1 Jan 2002 NOTE: 160 volts can injure or kill you. Use this circuit at your own risk. Transformer: Any small dual 120 volt primary transformer. Mine are PC mount types. Secondary winding(s) not used. Or, use a pair of back to back small low voltage transformers (e.g. 120 to 12 feeding 12 to 120). (You dont really need this transformer, but it is much safer to have your unit isolated from the AC power. I strongly encourage you to use it) Resistors: All ¼ watt 5 or 10% tolerance (not critical). The 2K trim- pot and 4.7K resistor set the current. I set mine at 1.11 ma which I think produces about 2.5 ppm per hour for one quart. KSP42: This is a 300 volt NPN transistor which costs less than 40 cents. I got mine from Jameco. LM334: This is an adjustable constant current regulator. It is rated at 10 ma and 40 volts max. In the circuit, both are considerably less. I got mine from Jameco for less than $1. Electrolytic capacitor: It can be anything with at least 33 mF and at least 250 volts. Diode: Can be 1N4004, 5, 6, or 7. [Note constant current regulator part of the circuit can be duplicated many times if you need to brew more than one quart at a time.] I put a Radio Shack neon lamp indicator across the primary of the transformer so one can see that the generator is on, and put it all in a Radio Shack plastic box. All parts are available from mail order dealers such as Jameco ( www.jameco.com ) and All Electronics ( www.allelectronics.com ). Total cost of the parts should be less than $15. By the way, All Electronics sells a timer board for $3.50 that works great with this circuit. You have to change the timing cap from 0.1 mF to 0.33 mF and use a 1 meg pot instead of the fixed resistor. Then you can set the time to 1 6 hours for automatic shutoff. Also, All Electronics sells 30 RPM 120 VAC motors that make great stirring motors. I think they are $2.50 each. I believe they were made for microwave oven turntables. See www.allcorp.com. I use a plastic paddle about one inch wide with the length extending close to the bottom of the jar. This paddle couples to motor shaft with a short piece of vinyl plastic tubing. Good health to you, Steve Young ------- End of forwarded message -------- ------- End of forwarded message --------
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