Hello guys
I need your assistance in calculating R1 R2 R3 and R4 resistors from the attached schematic. The requirements are that at 25V the opamp should output 2V and the opamp should be powered from a single 5V supply.
Also please let me know if what I am trying to achieve is correct.
- if the base of the transistor is off and no battery is connected then the opamp should output 0V
- if the base of the transistor is on but no battery is connected then the opamp should output 2V
- if the base of the transistor is on and the battery is connected then the opamp should output a value between 0 and 2 volts depending on the battery resistance (RL is used to simulate this resistance)
- if the base of the transistor is off but a 12V battery is connected then the opamp should output 0.96V
- if the battery is placed by mistake in reverse and the base of the transistor is off then the output should be 0.
Also please let me know the following:
1. is what I am trying to achieve correct or not?
2. in case of the reverse voltage on the opamp (+ and - not the supply), will the opamp survive?
3. what resistors I should change with potentiometer (only one if possible) in order to have possibility to adjust the output in case the resistors are not precise
4. is there any other method to measure the voltage between the specified points
5. regarding my schematic, could you also post the equations that lead to the calculated values or at least how you deduce them?
P.S. Please note that RL only simulates the battery internal resistance.