Does anyone have the schematic of the green circuit board inside of a servo?? It needs to have the feedback loop and the H bridge.
Please let me know Thanks.
Please let me know Thanks.
This is an industrial/hobby controller, but not for your typical model drone: http://www.uhu-servo.de/servo_en/UHU_Servo_Controller_300_en.pdf
And here's another link more focused on hobby servos: https://www.princeton.edu/~mae412/TEXT/NTRAK2002/292-302.pdf
If you want a particular brand, open it up and see what chip is used. Be aware that servos have evolved from discrete components to integrated to highly integrated circuits over the years.
The schematic shows a hobby RC servo.On the princinton were does the connections go?
View attachment 157063
My ground answer may be confusing. Assuming the servo wires are black red white. The ground is the black wire. The PWM is the white wire. And VCC is the red wire. If the coding is brown red orange/yellow, then brown = black, red = red, and orange/yellow = white.
The servo control IC in the above posts has the advantage that the position feedback mechanism uses a potentiometer as a voltage divider whose output is compared to a linear ramp generated by the IC. This is very well suited for the pan-tilt because that is exactly the sort of signal that it produces. It might be necessary to change the fixed resistors in series with the potentiometers in the the pan-tilt to get the required voltage range. The "top end" of the pots int he pan-tilt would be supplied from the servo IC.
The internal NPN drivers for the motor could be used directly (current limiting resistors needed) to drive the inputs of triac-output optocouplers to control triacs to run the AC motor. The external PNP transistors are not required (these controllers used external PNP transistors because putting them on-chip isn't compatible with the IC fabrication process used).
The servo control IC in the above posts has the advantage that the position feedback mechanism uses a potentiometer as a voltage divider whose output is compared to a linear ramp generated by the IC. This is very well suited for the pan-tilt because that is exactly the sort of signal that it produces. It might be necessary to change the fixed resistors in series with the potentiometers in the the pan-tilt to get the required voltage range. The "top end" of the pots int he pan-tilt would be supplied from the servo IC.
The internal NPN drivers for the motor could be used directly (current limiting resistors needed) to drive the inputs of triac-output optocouplers to control triacs to run the AC motor. The external PNP transistors are not required (these controllers used external PNP transistors because putting them on-chip isn't compatible with the IC fabrication process used).