Author Topic: SSR01 - substitute H1 with zener?  (Read 20 times)

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Offline tk-don

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SSR01 - substitute H1 with zener?
« on: March 10, 2019, 09:38:51 PM »

I'm building a 7V SSR01 using a 9V AC supply, which when rectified and accounting for losses should give nearly 12V output, which should be ok with the SSR01 with AD825 I hope.
The PCB will be partly visible through a perforated cardboard inside an old tube radio, and would like avoid any shining LEDs if possible.

Would it thus be possible just to use a 2.4V zener diode instead of H1, and just leave R3 at 2.2k? Or is the base current of the BC556B negatively affected by this (as I-V characteristics of zeners and LEDs are not the same)
Or would it be possible to even use a 3.3V zener like used as DZ1, possibly lowering the value of R3?
« Last Edit: March 11, 2019, 11:04:34 PM by tk-don »