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Old 26th Aug 2019, 3:46 pm   #5
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,557
Default Re: Boost the ringer current instead of ...

I have (I hope) attached a reverse-engineered (by me) circuit diagram of the ringer booster that was commonly sold in the UK some years ago (maybe BT-badged).

Note that the opto-isolator is a rather odd one with a very high current transfer ratio (ratio of LED current to output current). It will not work with just 'any old optoisolator'.
Attached Files
File Type: pdf REN_booster.pdf (458.7 KB, 95 views)
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