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shushi_boi

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- TL;DR Summary
- When using a relay (coil) in operating voltage at 1.5V, but the minimum operating amperage is rated differently from different components in the circuit that require 20mA, whereas the coil requires 93.8mA, can all components function together?

Hello, I'm using a "TQ2SA-1.5V Panasonic 2 Form C AS Single side stable, 1.5VDC 2A DPDT NON-LATCHING SMD Relay" (specifically the coil side of this relay) that is rated for 1.5 volts that is connected in series to this circuit (as the last device in this circuit shown below), which in this series 5VDC circuit, the main voltage supply dropped from 5V to 1.5V once it reaches the relay (hopefully my math is correct up to that point ).

Here are the links to devices that I'm using in this circuit for more information about them as well as a PDF file I'll include that I will be referencing for the Relay device, specifically its coil's electrical characteristics.

https://www.mouser.com/ProductDetail/769-TQ2SA-1.5V

Link to LED switch

https://www.amazon.com/gp/product/B00OT74FIS/?tag=pfamazon01-20

As shown in the image above, the circuit is being fed from a 4 Port Charging USB Hub through a USB jumper cable, which the other ports consume a total of 0.2545 amps, reducing the 1.48 amps supply to 1.23 amps for this port (which is capable of supplying up to a maximum of 2.4 amps) that I'm working on here. So I know that the total volts in this circuit would be 5 Volts, but not knowing the total resistance or total amperage of this circuit, I decided to use Ohms law to figure out the resistance, voltage drop and amperage of this circuit and of the components that I want to use.

having done further research on each component, such as the green LED switch (which the datasheet referenced in the image below shows that it's resistance is 105 Ohms when one divides Foward Nominal Voltage [or voltage drop] 2.1 by Forward Current 0.02 Amps), or the 1N4001 diode (which I couldn't find a forward resistance value online but read that it's forward voltage drop is always 0.7 volts, although I used my digital multimeter at home and on average most of these diodes that I have at home measured around 280 kiloOhms, which didn't make sense with the forward voltage drop which I divided the forward voltage drop by the 0.02 Amps value that I got from the LED switch which got me a calculated 30 ohms of resistance which was the value that I used) I was able to come up with some resistance and voltage drop values for these components (which I based the Forward Current value from the LED switch as the basis of this circuit's current), which having reached to the final component, which was the relay's coil which needed 1.5V to operate, I was able to drop the circuit's voltage up to 1.5 Volts, which is the minimum operating voltage for this coil by using X1 LED switch and X2 1N4001 Diodes. But as the image above indicates, from the datasheet (page 5) of the relay, the coil's minimum operating current is 93.8m Amps and 140m Watts, but having calculated to total current based off the resistance of all the components together my calculated total amperage is 20m Amps and 30m Watts (from calculated 191 Ohms total resistance).

My knowledge with circuitry is very basic and I am self taught for the most part so I'm not sure if I made mistakes in my calculations or how I would go about to correct them. But I understand that these graphs that I made are really messy so I tried to redraw a basic outline of this circuit down below.

Having calcuted these resistance and voltage drop values for these components, how can I fix this circuit so that the Coil Relay receives enough amperage to reach the 140mW goal? If all the other earlier ports from the USB charging Hub leave this circuit with a total current of 1.23A to work with, will this circuit draw more than 20mA in order to get the highest current consuming component to work (which would be the 93.8mA hungry relay coils)? If this happens, would the other components with the same voltage, but added amperage and wattage fry them like the LED switch? What would be the total amperage in this circuit and resistance, since most of these components would probably change in resistance value (which I'm guessing happens since the datasheets seem to imply this)? And are all of my questions close to the right answer or am I way off?

I'm sorry for asking too many questions about this circuit or if I asked questions that aren't relevant or are completely wrong, I'm sort of thinking more and more about this issue and trying to think of different possibilities

I feel that I made a lot of mistakes or that I have a lot of faulty assumptions behind my calucations and reasoning, but the part that is killing me the most is that I can't figure out what it is, I hit an empass and I feel a bit disapointed

I try not to ask too many novice questions, but I do appreciate the time and everyone's efforst to assist others in need, the answers that I've personally learned from this forum have been enlightening a very indespensible to me so from my end I'd like to thank everyone's continued assistance for others which continues to be very educational for many aspiring engineers such as myself

Here are the links to devices that I'm using in this circuit for more information about them as well as a PDF file I'll include that I will be referencing for the Relay device, specifically its coil's electrical characteristics.

https://www.mouser.com/ProductDetail/769-TQ2SA-1.5V

Link to LED switch

https://www.amazon.com/gp/product/B00OT74FIS/?tag=pfamazon01-20

As shown in the image above, the circuit is being fed from a 4 Port Charging USB Hub through a USB jumper cable, which the other ports consume a total of 0.2545 amps, reducing the 1.48 amps supply to 1.23 amps for this port (which is capable of supplying up to a maximum of 2.4 amps) that I'm working on here. So I know that the total volts in this circuit would be 5 Volts, but not knowing the total resistance or total amperage of this circuit, I decided to use Ohms law to figure out the resistance, voltage drop and amperage of this circuit and of the components that I want to use.

having done further research on each component, such as the green LED switch (which the datasheet referenced in the image below shows that it's resistance is 105 Ohms when one divides Foward Nominal Voltage [or voltage drop] 2.1 by Forward Current 0.02 Amps), or the 1N4001 diode (which I couldn't find a forward resistance value online but read that it's forward voltage drop is always 0.7 volts, although I used my digital multimeter at home and on average most of these diodes that I have at home measured around 280 kiloOhms, which didn't make sense with the forward voltage drop which I divided the forward voltage drop by the 0.02 Amps value that I got from the LED switch which got me a calculated 30 ohms of resistance which was the value that I used) I was able to come up with some resistance and voltage drop values for these components (which I based the Forward Current value from the LED switch as the basis of this circuit's current), which having reached to the final component, which was the relay's coil which needed 1.5V to operate, I was able to drop the circuit's voltage up to 1.5 Volts, which is the minimum operating voltage for this coil by using X1 LED switch and X2 1N4001 Diodes. But as the image above indicates, from the datasheet (page 5) of the relay, the coil's minimum operating current is 93.8m Amps and 140m Watts, but having calculated to total current based off the resistance of all the components together my calculated total amperage is 20m Amps and 30m Watts (from calculated 191 Ohms total resistance).

My knowledge with circuitry is very basic and I am self taught for the most part so I'm not sure if I made mistakes in my calculations or how I would go about to correct them. But I understand that these graphs that I made are really messy so I tried to redraw a basic outline of this circuit down below.

Having calcuted these resistance and voltage drop values for these components, how can I fix this circuit so that the Coil Relay receives enough amperage to reach the 140mW goal? If all the other earlier ports from the USB charging Hub leave this circuit with a total current of 1.23A to work with, will this circuit draw more than 20mA in order to get the highest current consuming component to work (which would be the 93.8mA hungry relay coils)? If this happens, would the other components with the same voltage, but added amperage and wattage fry them like the LED switch? What would be the total amperage in this circuit and resistance, since most of these components would probably change in resistance value (which I'm guessing happens since the datasheets seem to imply this)? And are all of my questions close to the right answer or am I way off?

I'm sorry for asking too many questions about this circuit or if I asked questions that aren't relevant or are completely wrong, I'm sort of thinking more and more about this issue and trying to think of different possibilities

I feel that I made a lot of mistakes or that I have a lot of faulty assumptions behind my calucations and reasoning, but the part that is killing me the most is that I can't figure out what it is, I hit an empass and I feel a bit disapointed

I try not to ask too many novice questions, but I do appreciate the time and everyone's efforst to assist others in need, the answers that I've personally learned from this forum have been enlightening a very indespensible to me so from my end I'd like to thank everyone's continued assistance for others which continues to be very educational for many aspiring engineers such as myself

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