Gel disinfectant distributor circuit

Hi,

i have this circuit that works at 5V will you help me to operate it at 12V?



and what changes should I make to replace the sensor receiver and IR transmitter, with these more easily available?

https://win.adrirobot.it/datasheet/optoelettronica/pdf/IR-TX-LL-503IRC2V-2AD.pdf

https://win.adrirobot.it/datasheet/optoelettronica/pdf/IR-RX-PD333-3B-H0-L2.pdf

Thanks...

Hi,

honestly I´d use a very simple method: just use a 12V --> 5V DCDC converter.

Klaus

yes I know...

but wanting to use the 12v circuit only by changing the resistances?

Hi,

LM358 & LM555 can be operated at 12 V. Capacitor voltage ratings are fine.

Resistors R4, R5, R7, R8 and (both) R3 should be worke fine at 12 V according to their power rating.
The potentiometers V1 and V2 do not state any power rating, if they are also rated with 1/4 W there shouldn't be a problem as well (they are high valued).

Depending on your LED voltage drop at LD1, R9 should be increased due to the power rating of 1/4 W. Further, the LED forward current will be probably be above 20 mA (I_D = (12V - 1.6 V) / 470 Ω = 22.1 mA), which may exceed the LED's maximum current rating --> increase R9.

Increase R1 proportional to your voltage increase, to ensure the same forward diode current and thus radiation intensity. Keep the power handling of your new R1 in mind!
OPA589 can widthstand a voltage up to 30 V and handle a current up to 50 mA, so there should not be a problem.

I hope I haven't overlooked something, and maybe someone has an other opinion .

Greets

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I meant OP598 ;-)

Hi,

O.K.
What´s the benefit?
I see that the generated heat is about 240% than before. But that´s usually not a benefit - unless you want to operate it at very low ambient temperatures.

Klaus

KlausST said:

Hi,

O.K.
What´s the benefit?
I see that the generated heat is about 240% than before. But that´s usually not a benefit - unless you want to operate it at very low ambient temperatures.

Klaus

Click to expand...

I agree with you, I also would use a DCDC converter.
But we do not know the motivations of tnnedaboard why he is aiming to operate the circuit directly with 12 V. Maybe he will tell us :wink:.

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As I have not more information I considered only "safe" operation at 12 V without blowing up the circuitry.

Hi,

sorry for a possible misunderstanding, my post was addressed to the OP.

Klaus

Yes by assuming the the quiescent current is the same as for 5 V, someone may expect an even higher power consumption at 12 V than 240%.