In order to solve this equation, we choose the value of one resistor and then based on that resistor value compute the value of the other resistor based on this formula. Consult the data sheets to determine which works best. I need a simple, single directionnal level shifter for 3. Shouldn’t the drop of the transistor be 0. I like your solution.

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So, why wouldn’t such a converter work? We will now get into the details of why the various components are needed for the circuit and bufffer to choose the values for them.

The circuit configuration you have is called an emitter-follower, and it not used for switching, its used for buffering analog signals typically. So the first thing is 2j2222a decide how much voltage we’re going to supply this circuit. You should have get around This circuit can be added to voltage line that needs to be buffered, which allows all nuffer voltage to be transferred over, while giving out a low impedance output so that a load can be powered.

Simulation Models: 2NA

Why this matters in regards to the voltage that we supply to the base is that whatever voltage comes into the circuit has a floor of 0. The circuit shown will not pull-up clear to 5V, but it will increase the high-level input voltage to the 5V logic by the amount of one diode voltage drop appx 0.


For this circuit, we choose the 2N transistor. Anindo Ghosh 46k 7 84 This is typically V on most transistors.

The next thing we must consider is buffet value of the resistance that the capacitor sees. I like your solution. I am not sure I understand that schematic it doesn’t use conventional symbols. And now we’ve solved for all the values of the components in the circuit. The AC signal will only be able to swing as far as the DC voltage biasing allows it.

Single transistor level up shifter – Electrical Engineering Stack Exchange

So they function as coupling capacitors. Resistors R 1 and R 2 are in parallel. To counteract this difference I simply paralleled biffer 2Ns which evened up the effective Vce sat voltages by lowering the current through each and made the waveform more symmetrical.

The Arduino can only generate 5V, so the emitter in your circuit has to be less than 5V about 0. Now we move onto the second capacitor. R EQ is the resistance that the output capacitor sees in the circuit. If you select a DC value 2n222a low, you will cause the signal to clip earlier at the bottom of the waveform. Olin can be a little picky. Therefore, with a power supply of biffer and a ground 0. Also, you have pretty much rediscovered US patentfrom the s. So based on this point, we want buffwr voltage at the base to be midway between 12V, the supply voltage, and 0.


On the other end of the spectrum, the transistor can swing down to near ground, about 0.

How to Build a Buffer Circuit with a Transistor

And it’s chosen similarly to the first capacitor. There are many options on the internet, some using a logic ic and some using 2 NPN transistors converter and inverterbut I never found an option using only a single transistor and 2 resistors.

Post as a guest Name. I like that 3rd solution, but I think it’s subject to the same input impedance limitation as my original schematics For another, it isn’t a completely accurate voltage follower circuit.

The only difference in voltage between the base voltage and emitter voltage is the diode voltage drop between the 2 junctions. Otherwise that circuit will not work.

Positioning the transistor at the midpoint of those voltages allows for the maximum swing of the AC signal from the ceiling to the floor.