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  1. 25-08-2012 #24
    boldford's Avatar
    Lives in Telford, United Kingdom.
    boldford
    Last Activity: 27-04-2020 Has been a member for 9-10 years. Has a total post count of 114. Received thanks 2 times, giving thanks to others 2 times.
    Quote Originally Posted by irving2008 View Post
    Ah, so the transistor is not saturating. with 100R load, the collector current therefore is (5 - 1.6)/100 = 34mA, whereas it needs to be (5-0.5)/100 = 45mA, so the LED needs to be driven harder as previously discussed. However the 74HC14 clamps at 20mA, so there may be a limiting factor here... try reducing R1 from 1k to around 450R or so, theres no point in going lower... if that doesnt improve things then its not going to get better without significant rework
    As stated earlier R1 is 330R, so it looks like I need to have a think if I'm going to use this BoB in the way I had intended.
    Last edited by boldford; 26-08-2012 at 09:24 AM.
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