Servos

PWM hobby servos and serial bus servos share nothing but a three-wire connector. A bus servo daisy-chains, reports position back and can run as a continuous motor; a PWM servo takes a pulse and goes quiet.

9g micros and clutch PWM servos, IP67 metal servos to 35KG, and ST/SC/CF serial bus servos (2.3kg to 120kg.cm at 24V) — protocol matters as much as torque rating here.

The ST3215, ST3235 (30kg.cm) and SC15 serial bus servos use TTL UART with two-way feedback, switchable servo/motor modes and programmable 360° magnetic encoders; up to 253 chain on one bus.
DFRobot's clutch servos (2Kg/6Kg, 180° or 300°) mechanically slip under external force and cut power if blocked for 5 seconds — worth the swap where collisions would strip gears.
Torque spans 0.45kg micro 360° servos to the 35KG IP67 waterproof metal servo and the 120kg.cm RSBL120-24 bus servo, which runs at 24V — not a drop-in for a 4.8–6V hobby rail.

RC servos

Servo control pulse + external servo power

A servo is the actuator, not a driver board. Treat torque, travel angle, gearing, size, connector and supply current as the deciding factors.

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All parts

99 parts

RC servos

9g 180° Micro Servo (1.6kg)

Complete 9 g 180° RC micro servo, not a motor driver board. Match voltage, torque, travel angle, connector, mechanical size and stall-current headroom.

$3.50

Digital Servo (DS-929MG)

Digital RC servo with metal gearing. Match servo voltage, torque, travel, spline/horn, size, connector and stall-current headroom rather than comparing it to motor-driver boards.

£9.60