Product Tips & Tutorials: Servos
Analog vs Digital Servos
Posted by on 24 August 2012 03:07 PM

The difference between a Digital Servo and an Analog Servo isn't the physical or component aspect of the servos. The motors, gears, and even feedback potentiometer operate in the same manner. The difference between the two is the signal and how it is processed from the reciever to the servo and how the servo uses this information to send power to the motor.

Analog Servo

Analog Servos control the speed of motors by applying ON/OFF voltage signals to the motor. These signals come in pulses, and have been standardized to 50 cycles per second. The voltage ratings for these pulses are constant. The longer the pulse is, the faster the motor turns and the more torque it will produce. At rest, there is no voltage going to the motor, but if a transmitter sends a command or signal to the servo, a short pulse duration will be sent to the motor. Analog Servos don't react fast enough to produce much torque when given small commands. Analog Servos are cheaper to buy, but you will not get the best response time or sensitivity when it comes to controlling your RC product. This is especially critical if you're getting into more advanced flying with RC Helicopters or RC Planes.

Digital Servo

Digital Servos have a small microprocessor inside that analyzes the reciever signals and process them into very high frequency voltage pulses to the motor. Unlike the Analog Servo, which sends out 50 pulses per second, the Digital Servo has the ability to send pulses upwards 300 pulses per second. The pulses are shorter in length, but with so many voltage pulses, the motor speeds up faster and provides constant torque. You can actually hear the high frequencies when loads are pushed through to the motor. This allows for faster response time and smoother acceleration as a reult. Digital Servos do consume a lot of power though, one of the drawbacks to having quicker response. 

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