NE555 Pulse Module: Features: The output frequency of this module can be adjusted in 3 leves: Low frequency band (L) : 50hz-1.3khz,Medium frequency band (M) : 570hz-16khz, High frequency band (H) : 5.3 khz-100 KHZ Used as a square wave signal generator, generating square wave signal for experimental development. Generate the square wave signal for driver the stepping motor. Generate adjustable pulse for use by MCU. Generate adjustable pulse and control related circuits. NE555 PWM Module: Features: Used as PWM signal generator, generating square wave PWM for experimental development. The output frequency of this module can be adjusted in 3 leves: Low frequency band (L) : 50hz-1.3khz,Medium frequency band (M) : 570hz-16khz,High frequency band (H) : 5.3 khz-100 KHZ Generate the square wave signal for driver the stepping motor. Generate adjustable pulse for power drive circuit. Generate adjustable pulse and control related circuits. Specifications: Type: NE555 Pulse Module , NE555 PWM Module (Optional) Main chip: NE555 Input voltage: 5V-12VDC. Input current: ≥100MA Output amplitude: 4.2v v-pp to 11.4v v-pp (depending on the input voltage) Maximum output current: ≥15MA (5V power supply, v-pp >50%), 35MA (12V power supply, V-PP> 50%) NE555 PWM Module Output duty ratio: 2-98% adjustable Weight:10-21g Package includes: 1 x NE555 Module