Christmas Spirit Crank

RE: Christmas Spirit Crank

jw0752 — Sun, 29 Dec 2019 05:43:05 GMT

Here is an example of what I was talking about. I am not an expert and once the other guys check out your posting they may say you were right and my ideas are off. The guys will also perhaps have suggestions for the values of the resistors for the pull up and buffers between the 3914 and the 7414 and the MOSFET. I would tell you what I have used but it would just be a guess.

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John

RE: Christmas Spirit Crank

jw0752 — Sun, 29 Dec 2019 05:21:19 GMT

Hi Jason,

I noticed one other thing that you may want to look into. The LM3914 is designed to turn on LEDs by pulling the outputs low. This means that you will need pull up resistors on each of your outputs and an inverter between the LM3914 and your MOSFETs if you want the MOSFETs to turn on the LEDS in the same manner that the original LM3914 did.

John

RE: Christmas Spirit Crank

jw0752 — Sun, 29 Dec 2019 05:08:19 GMT

Hi Jason,

I suspect you will want the LEDs above the MOSFETS so that your gate voltage doesn't have to be so high. If the Source of the MOSFET is at ground and the Drain of the MOSFET is being supplied by the cathodes of the LEDs then a digital high from the 3914 to the Gates will turn the MOSFETS on.

John