Simple TDA7274 Based Low Voltage Motor Speed Controller Circuit is useful and easy to make.
Circuit is efficient and precise with speed adjust.
TDA7274 IC is motor driver for low voltage and for low power DC motors.
It works from 1.8V to 6V and has built-in voltage reference.
Output is up to 700mA and is stable with temperature change.
Vs supply choose as per motor need from 1.8V to 6V
Max output current is about 700mA.
Circuit Working:

Parts List:
Component | Specification | Quantity |
---|---|---|
Resistors | 220Ω, 2k 1/4 watt | 1 each |
Potentiometer 10k | 1 | |
Capacitors | Electrolytic 4.7µF 25V | 1 |
Electrolytic 1µF 25V | 1 | |
Semiconductors | IC TDA7274 | 1 |
DC Motor | 1 |
Circuit uses TDA7274 to control motor speed by input voltage.
R1, R2 and VR1 adjust control voltage for accurate speed.
TDA7274 IC1 manage power to motor.
R1, R2 and VR1 make voltage divider to change control signal.
C1 and C2 cut noise and keep circuit smooth.
Motor get correct voltage for different speeds.
Formula:
Below are the formulas with calculations for Simple TDA7274 Based Low Voltage Motor Speed Controller Circuit:
Voltage divider formula:
Vcontrol = Vs × (VR1 / (R2 + VR1))
where:
- Vcontrol is voltage to control pin
- Vs is the supply voltage
- R2, VR1 are the voltage divider parts.
How to Build:
Below are the steps for to build a Simple TDA7274 Based Low Voltage Motor Speed Controller Circuit:
- Gather all the parts as per the circuit diagram
- Connect pin 3 of IC1 to the positive supply.
- Connect pin 4 of IC1 to one end of VR1.
- Connect pin 5 of IC1 to ground.
- Connect pin 6 of IC1 between R1 and R2.
- Connect pin 8 of IC1 between R2 and VR1.
- Connect the positive side of capacitor C1 to the positive supply and the negative side goes to pin 6 of IC1.
- Connect one end of the DC motor to the positive supply and the other end goes to pin 4 of IC1.
- Connect the positive side of capacitor C2 to the positive supply and the negative side go to pin 4 of IC1.
Conclusion:
Simple TDA7274 Based Low Voltage Motor Speed Controller Circuit is build easily.
The speed changes by adjusting the resistors.
Circuit is easy with no complex parts needed.
It is good for small motor projects with stable and adjustable speed.
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