Linking diodes - Page 1
Forum section: electronics / beginners

author: RacerDave
author_rank: Newbie
timestamp: November 30, 2019, 06:22:46 am
content: Does anyone know how to take 6 different diodes to make from 3v-12v. I am trying to make 6 bulb led power meter. The more volts you turn on the more lights light up using 12v led diodes. I now I can use 32 1n 4007 diodes but would like to use just 6 stepping up each time from around 2v-12v. I pretty sure this is an easy one but I do not have the knowledge to do this at this time. Thank you in advance!

author: james_s
author_rank: Super Contributor
timestamp: November 30, 2019, 06:26:45 am
content: I read your post twice and I still have no idea what it is you're actually trying to build, could you clarify? When you say diodes do you mean LEDs (Light Emitting Diodes) or are you talking about regular diodes? What do you mean by turning on more Volts?

author: RacerDave
author_rank: Newbie
timestamp: November 30, 2019, 06:59:48 am
content: Sorry for the confusion. I am using light emitting diodes 6 colors one for each step up in power as applied with a controller when the trigger is squeezed making more lights come on. I made one using rectifier 1n 4007 diodes linked together but it takes 33 of them. I want to use just 6 different diodes connecting the 12v emitting diodes to them from 2v-12v. It is like a power meter. Hope this helps.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 30, 2019, 07:09:36 am
content: Do you want the passive kind where the lowest ones glow super bright and the highest ones glow dimly? That's a stack of LEDs, with a resistor in parallel with all but the bottom one, and one resistor in series with the input. Typical might be 100 ohms for the resistors.For equal lighting and sharp thresholds, get a LM3914 (while you still can, they're going obsolete) and follow the circuit in the datasheet.Tim

author: Zero999
author_rank: Super Contributor
timestamp: November 30, 2019, 08:33:06 am
content: Quote from: RacerDave on November 30, 2019, 06:59:48 amIt seems like the component you're looking for is a zener diode.There are much better ways to do this, such as the LM3914, although genuine parts are expensive and getting difficult to get hold of now. Another is with a comparator IC, such as the LM339, a suitable voltage reference and a potential difider.

author: Moshly
author_rank: Regular Contributor
timestamp: November 30, 2019, 10:04:38 am
content: You could probably use a modified version of this VU meter circuitMake it 6 segments long, replace the input 4u7 cap with say ~1k resistor & make all the resistors connected to the transistor bases the same, try ~10k.http://www.talkingelectronics.com/projects/StereoVUmeter/StereoVU.html

author: james_s
author_rank: Super Contributor
timestamp: November 30, 2019, 07:33:44 pm
content: LM3914 is the way to go for this sort of thing IMO, they're still easy to get and inexpensive from China. Are they genuine? I doubt it, but they seem to work fine, it's not exactly a high tech part. You can even get complete modules in various forms.https://www.ebay.com/itm/LM3914-3-7-V-Lithium-Capacity-Indicator-Red-Geen-Blue-LED-Display-Module-Hot/113805056325?