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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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23rd May 2020, 1:42 pm | #21 |
Hexode
Join Date: Jun 2018
Location: Buckinghamshire, UK.
Posts: 387
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Re: Low voltage indicator for 90v circuit
BC547 has a max Vceo of 45v.
Cheers |
23rd May 2020, 2:41 pm | #22 |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 3,988
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Re: Low voltage indicator for 90v circuit
That is the same as the SMD SOT23 specified. Thanks for pointing it out. What would you device suggest ?
John.
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23rd May 2020, 2:44 pm | #23 |
Guest
Posts: n/a
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Re: Low voltage indicator for 90v circuit
Brilliant, I am rather chuffed that it works when built. You are stretching the voltage rating of the BC547 (rated 45V) a bit, modern components are so good that I am not surprised it is OK. 78V, the simulation was smack on.
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23rd May 2020, 7:43 pm | #24 |
Hexode
Join Date: Jun 2018
Location: Buckinghamshire, UK.
Posts: 387
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Re: Low voltage indicator for 90v circuit
Many people seem to keep MPSA42 (npn) and MPSA92 (pnp) devices on hand as general purpose higher voltage transistors.
Both Vceo= 300v, with gain good enough for many purposes. Cheers |
23rd May 2020, 9:16 pm | #25 | |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 3,988
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Re: Low voltage indicator for 90v circuit
Quote:
Thank you, I have just ordered 10 of each, I may only use one but look handy just in case I need any more. While looking for a suitable transistor I found an interesting Diode, I had better start another thread about it. John.
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29th Jun 2020, 12:02 pm | #26 |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 3,988
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Re: Low voltage indicator for 90v circuit
I'm very pleased with the above circuit and wonder if it can be done for a 9v circuit ? light on at about 7v. I have been playing with my bread board but not making much progress. I have 3.3v 4.7v and 10v Zener diodes available. Please can anyone help.
TIA John.
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My favourite text message "I'll be there in five minutes, if not read again" |