- ua208a - 1 Update
- improvised voltage reference - 2 Updates
- Scumacher 1042A-PE battery charger has no output. - 2 Updates
| bitrex <user@example.net>: Aug 25 11:26AM -0400 Is there a suitable modern replacement for the ua208a TO-99 can-type op amp as used in e.g. the HP oven oscillators, that's available and doesn't cost an arm and a leg? <https://datasheetspdf.com/pdf/1305470/Fairchild/UA208A/1> Probably less expensive to just buy another module, maybe |
| ehsjr <ehsjr@verizon.net>: Aug 24 06:44PM -0400 On 8/23/2022 10:24 PM, bob prohaska wrote: You want a precision that is doomed by the technique you intend to use - stacking cells. Instead, build a voltage reference using a single IC: ADR01 available from Digikey https://www.digikey.com/en/products/detail/analog-devices-inc/ADR01AUJZ-REEL7/996117 It provides 10V output at +/- point one percent (.1%) Calibrate your meters to that. Ed |
| amdx <amdx@knology.net>: Aug 25 05:29AM -0500 On 8/23/2022 9:24 PM, bob prohaska wrote: > CR2032 cells are readily available, but voltage details are scarce. > Thanks for reading, > bob prohaska Aliexpress, Ebay and Amazon have some for under $10, and more for under $20. |
| David Farber <farberbear.unspam@aol.com>: Aug 24 05:34PM -0700 On 8/21/2022 9:28 PM, Phil Allison wrote: > ** Read my first post again. > SCRs, once triggered, conduct large currents with small voltage drops. > ..... Phil Finally got around to testing the SCR and it works perfectly. The only other active components other than the power supply diodes are the two IC's, LM2901 and LM2903. Thanks for your reply. -- David Farber Los Osos, CA |
| Phil Allison <pallison49@gmail.com>: Aug 24 07:00PM -0700 David Farber wrote: > > ** Read my first post again. > > SCRs, once triggered, conduct large currents with small voltage drops. > Finally got around to testing the SCR and it works perfectly. ** Yep - expected that. The only > other active components other than the power supply diodes are the two > IC's, LM2901 and LM2903. ** I see a TO92 pak transistor near the SCR. Lotta resistors about too. Dead easy to check them for opens. .... Phil |
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