I'm learning about Diodes lately all alone with little help from one gentleman/lady on Reddit who was only one to help until i have got this website and watched few videos about diodes, but still i do not get them fully to understand by their Values and Codes to do specific task.
Since i understand how they function finally, i still can't get them by Values, i'll explain.
First about Circuit i'm building:
3.6V - 3x1.2V 2400mAh AA rechargable batteries
5 Red LEDs 20mA 2V - 0805 ... resistor for LED's 21Ω
5 Blue LEDs 20mA 2.8V - 0805 ... resistor for LED's 10.8Ω
6 White LEDs 20mA 2.8V - 0805
8 White LEDs 20mA 2.8V - 0805
... resistor from 1.st Switch 3.58Ω (I have found how to search code for SMD resistor or colour code for ordinary resistor... which is not my best side)
= 14 White LEDs separeted from others with a diode (on pictures are 2 diodes but i have change that, i think it's better to separate with 1 diode)
SPDT Switch micro
SPST Switch micro
Diode (the trouble)
On pictures there's simple ordinary diode, but i have found and was adviced that Schottkey diode will be better and that's right, at first i have thought that if i put Vf 3.6V i'll get 2.8V for LED's as for example diode needs 0.8V or 800mV to work or something like that... ""that worked well""! hahaha... Later on Reddit person told me that that's wrong and i figured out somehow that i need diode Vf 0.8V or 800mV for powersource of 3.6V to gain 2.8V for LEDs but problem is not solved i need to regulate mA and i need 280mA (for full capacity of all LEDs) but i do not want use full capacity but for 3.5mA per LED less which means 14x3.5= 49mA less for all LEDs so in total i need 231mA. Now i'm not certain what to do for "If"... should i put If 231mA (closed number is 250 on one producer webpage) or put higher A (amps) then regulate it with current limiting resistors and will they have impact to V?
1. What should I/We be carefull about when choosing Diode?
2. How to read their designations, are they similar to resistors for example - SMD - 32X/S=21Ω, 04X/S - 10R8=10.8Ω?
3. How to calculate Vf and If for needed circuit? As mentioned person form Reddit told me and i understood, "If" can be high to "A" but when are "mA" needed that's how much "mA" will be drained from diode, is it correct?
- For example if "If" is 3A, but if circuit drains 300mA, 300mA will be drained form diode no matter of If 3A as it is limit how much diode can withstand in total.
4. How are their rating of their size and if we need for example 0805 diode how can we find same/similar diode with needed values?