PWM马达/灯控制器电路-PWMMotor/LightController

PWM马达/灯控制器电路-PWM Motor/Light Controller

A pulse width modulator (PWM) is a device that may be used as an efficient light dimmer or DC motor speed controller. The circuit described here is a general purpose device that can control DC devices which draw up to a few amps of current. The circuit may be used in 12 Volt and 24 Volt systems with a few minor changes. This device has been used to control the brightness of an automotive tail lamp and as a motor speed control for small DC fans of the type used in computer power supplies. A PWM circuit works by making a square wave with a variable border=0>

SPECIFICATIONS
PWM Frequency: 400 Hz
Current Capacity: 3 Amps with IRF521 FET, more with IRFZ34N FET
PWM circuit current: 1.5 ma @ 12V with no LED and no load
Operating Voltage: 12V or 24V depending border=0>

CONSTRUCTON
The prototype for this circuit was constructed height=445 src="/data/attachment/portal/201007/ET22485201007202059081.jpg" width=615 border=0>

PARTS
U1:LM324N quad op-amp
U2:78L12 12 volt regulator
Q1:IRF521 N channel MosFet
D1:1N4004 silicon diode
LED1 Red LED
C1: 0.01uF ceramic disc capacitor, 25V
C2-C5:0.1uF ceramic disk capacitor, 50V
R1-R4:100K 1/4W resistor
R5:47K 1/4W resistor
R6-R7:3.9K 1/4W resistor
R8:2.7K 1/4W resistor
VR1:10K linear potentiometer
F1:3 Amp, 28V DC fast blow fuse
S1:toggle switch, 5 Amps

USE
This circuit will work as a DC lamp dimmer, small motor controller, and even as a small heater controller. It would make a great speed control for a solar powered electric train. I have not tried the circuit with larger motors, in theory, it should work in applications such as a bicycle motor drive system, if you experiment with this, be sure to include an easily accessible emergency power disconnect switch in case the FET shorts border=0>

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