Tag Archive: ULN2003


A 40 watt fluorescent tube lamp or two 20-watt tubes in series will be driven by this circuit but this circuit will produce less brightness than usual, since this circuit only deliver 6-12 Watts. This circuit draws 0.9-1.2 Amps for 2 x 20 watt tubes, or 0.45-0.9A for 1 x 20 watt tube, depending on the potentiometer setting. Here is the schematic diagram of the circuit:

The transformer is wound on a ferrite rod 10mm diameter and 8cm long. The diameter of the wire is fairly critical but has been successfully implemented using 0.28mm wire for all the windings in the prototype. When the circuit is operating, do not remove the tube as the spikes produced by the transformer will damage the transistor.

ICL7107 CD4017 2N3055 LM3914 IRF3205 PT4115 2N2222A
NRF24L01 A1015 DS18B20 ICL7107 NE5532 MC34063 ULN2003

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The simplest way to drive stepper motor having lower current rating is using ULN2003. The ULN2003 contains seven darlington transistors. The ULN2003 can pass upto 500mA per channel and has an internal voltage drop of about 1V when on. It also contains internal clamp diodes to dissipate voltage spikes when driving inductive loads. The circuit for driving stepper motor using ULN2003 is shown below.

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For higher current torque motors, you can use TIP120. The advantage is that the TIP120 can pass more current along with heat sink. The disadvantages are that the more wiring is required and four TIP120 is used to control the motor.