Oxygen emitter driver controller electronic circuit

OXYGEN EMITTER DRIVER CONTROLLER ELECTRONIC CIRCUIT SERIES

What they have not pointed out though, is that while this would destroy your BJT, wich is really cheap, it would most likely also destroy your Arduino as the short circuit current through the BJT is drawn directly from your Arduino, and is much higher than the 20 or so milliamps that an Arduino pin can provide.What is claimed and desired to be secured byДЎ. This is what causes the voltage to drop at the MOS gate even thought current is still flowing from C to B through the 10k resistor.ДЄnd like others have pointed out earlier, a BJT base always need to be driven through a resistor as the BJT's internal resistance from base to emitter is so low you can basically call it a short circuit. And reversely if the resistance closer to the voltage source is the smaller one, then the voltage in between them would be closer to the voltage source (8v).

OXYGEN EMITTER DRIVER CONTROLLER ELECTRONIC CIRCUIT SERIES

(From C to B to GND).ДЄs you may know, 2 resistances in series between a voltage source and GND is what we call a resistive voltage divider (IF you don't know what this is you should Google it, it is a simple concept) When the resistance closest to ground is much lower than the one closest to your voltage source, the voltage between the resistances (in this case at point B) will be closer to GND (0v). But when the BJT turns on and provides a path from B to ground you can more or less view the BJT as a low-value resistor, as it has a very much lower resistance than 10kOhm This means that you now have 2 resistances in series between your 8 volts and ground. The 10k resistor between B and C allways delivers current to node B. DO Keep in mind that this is quite a bit simplified This is not strange att all considering that no one here seems to want to just Keep it simple, so i thought i'd give it a go. These discussions are rather advanced in my opinion, as you were asking about fundamentals that i gather from your follow up questions that you have not yet understood. Lowers/overrides that voltage coming from point C ? I hope I got my How come that the transistor 'breaks' that from point D to B and No, there is a 10k resistor in between B and C. When theДЄrduino pin is in HIGH state, point D measures around 0.3v.ДЄccording to my understanding point B is always on 8v because it get's When the Arduino pin is in LOW state, point D measures 8V. value of the base resistor.Д«eta minimum for 2n3904 is somewhere of 40, so Ib has to be >= 20uA. As we know Ic=Beta*Ib, you can calculate Ib, then the max. If the transistor would conduct withot any loss (zero resistance) the collector current would be 8V/10kohm= 0.8mA.

The value is around 4.7 kohm, it has to pass enough base current, so that BJT goes in saturation region - operation of the transistor as a switch. This resistor is the base resistor of the NPN BJT. It has no relation to the 2A of the PMOS switch. What's the value of R55, how is it calculated and is it related to If VDD changes, or if the 10 k resistor changes, or if the switched voltage is not 8 V, then you should recalculate R55.

So you can use a 33 k resistor (33 k is a standard value). So we want to set that equal to 80 uA and solve for R55. Typical base voltage in a circuit like this will be about 0.6 V.Д«ase current is VDD - 0.6 V / R55. The collector current is 8 V / 10 k = 800 uA. You are using 2n3904 as a saturated switch, so you want the base current to be about 0.1 x the collector current (more is also OK). R55 controls the amount of current in the base of 2n3904. So the 10k resistor pulls point B high, but when you turn on 2n3904, it pulls point B down, and it pulls a lot harder than the resistor so it wins the tug-of-war. The 10k resistor pulls point B high (to 8V) but when 2n3904 is turned 'ON' then it provides a low impedance path from point B to GND.

Oxygen emitter driver controller electronic circuit