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I just finished the LERA and hooked it up to the Mistress, it works but I feel like the range is a bit on the low side
I think it has to do with the Lera being designed for speed pots ranging from 25K to 250K though in the page it says it was tested with a Ross flanger which has a 500K pot I think
The photocell I used is 8-24K light and 500K dark and I tested it with the LED and photocell not being wrapped with anything, they are just out there
The highest speed will be during the minimum resistance of (LDR + 10k adjustment pot), which will occur when the LED is brightest. So reducing the 10k pot to minimum, and using an LDR with the lowest possible light-on resistance, will give you the fastest possible maximum speed. You may need to select an LDR with lower than 8k-24k light-on resistance. There are some as low as 400R-10k or 500R-15k including Silonex NSL 7530, 7532, 5152 and 4960. They all have 1M or more nominal dark resistance.
mauman wrote: ↑03 Sep 2022, 19:10
The highest speed will be during the minimum resistance of (LDR + 10k adjustment pot), which will occur when the LED is brightest. So reducing the 10k pot to minimum, and using an LDR with the lowest possible light-on resistance, will give you the fastest possible maximum speed. You may need to select an LDR with lower than 8k-24k light-on resistance. There are some as low as 400R-10k or 500R-15k including Silonex NSL 7530, 7532, 5152 and 4960. They all have 1M or more nominal dark resistance.
What I dont understand is the 8K-24K thing, like, which of these numbers should I pay attention to? Cos I've seen LDRs that are 500R-10K
8k/24k is a minimum/maximum rating with the light on. LDRs will usually have a set of ratings that include (1) a minimum and maximum for light-on resistance, in your case > 8k ohms and < 24k ohms, and (2) a minimum value for light-off resistance, in your case > 500k ohms. So if you tested a dozen of your selected LDRs, they should all measure between 8k and 24k in the light, and greater than 500k in the dark. Each one will be different.
In this application, you'd like a faster maximum speed, which means a lower minimum resistance with the light on. If your current LDR measures 10k (I'm assuming) in the light, look for one that's rated lower than that for light-on, such as >400R/<10k or >500R/<15k. The light-off value (yours is >500k) doesn't matter as much but I'd go for 1meg or more, since that's the value of your original Speed pot. You'll need to measure the light-on resistance of your existing and replacement LDRs, since your existing one could be anywhere from 8k to 24k, and a replacement rated 500R/15k could actually be higher than your existing one. I usually get a handful and select for the one I want.
So a light-on rating lower than your current one would help, that's the pair of lower numbers.
This is putting aside lots of other metrics like peak sensitivity (light color in nm) and rise/fall times (how fast or slow the LDR resistance changes when you add or remove light.) In this application, those are not as important as the resistance.
mauman wrote: ↑04 Sep 2022, 23:18
8k/24k is a minimum/maximum rating with the light on. LDRs will usually have a set of ratings that include (1) a minimum and maximum for light-on resistance, in your case > 8k ohms and < 24k ohms, and (2) a minimum value for light-off resistance, in your case > 500k ohms. So if you tested a dozen of your selected LDRs, they should all measure between 8k and 24k in the light, and greater than 500k in the dark. Each one will be different.
In this application, you'd like a faster maximum speed, which means a lower minimum resistance with the light on. If your current LDR measures 10k (I'm assuming) in the light, look for one that's rated lower than that for light-on, such as >400R/<10k or >500R/<15k. The light-off value (yours is >500k) doesn't matter as much but I'd go for 1meg or more, since that's the value of your original Speed pot. You'll need to measure the light-on resistance of your existing and replacement LDRs, since your existing one could be anywhere from 8k to 24k, and a replacement rated 500R/15k could actually be higher than your existing one. I usually get a handful and select for the one I want.
So a light-on rating lower than your current one would help, that's the pair of lower numbers.
This is putting aside lots of other metrics like peak sensitivity (light color in nm) and rise/fall times (how fast or slow the LDR resistance changes when you add or remove light.) In this application, those are not as important as the resistance.
Thanks! I went with a .7-2K light and 1M dark LDR, no kill like overkill right? I think I can simply adjust this later on
