High Precision Low Cost Adjustable Constant Current Source Output 0 to 2.5A

Current sources are widely used in industrial, power supply, LED drivers and other equipment. The project has been developed using the AD8276 difference amplifier and the AD8603 op-amp. Current source using the low power AD8276 difference amplifier and the AD8603 op amp are affordable, flexible, and is small in size. Performance characteristics such as initial error, temperature drift, and power dissipation make the AD8276 and the AD8603 ideal candidates for such project. The circuit provides current 0 to 2.5Amps, input supply 12 to 15V DC. I have tested this board with 4.7E/10W X3 parallel resistors.

Download PDF Schematic

Download AD8276 Data Sheet

Download AD8603 Data Sheet


  • Input 12 to 15V DC
  • Load Current Up to 2.5Amps
  • Current Adjustable 0 to 2.5Amps
  • On Board Trimmer Pot to Adjust the Current
  • Required Large Size Heatsink for full load 2.5Amps

Solid State DC Switching using Mosfet-Arduino nano dc-ssr shield

The simple DC switching possible with this MOSFET board, the board is made in form of Arduino Nano shield, the board can be used to drive inductive load as well as resistive load, possible application for the shield are LED dimmer, DC Motor speed controller, DC load ON/OFF, solenoid driver, and lamp dimmer. D2 provided for back EMF protection which helps to use an inductive load like DC motor or solenoid. The directly seats on top of Arduino Nano, Screw terminal provided to connect the load and Dc supply. This N-Channel MOSFET has been produced using a proprietary PowerTrench® technology to deliver low RDS(on) and optimized BVDSS capability to offer superior performance benefit in the application. FDD8876 MOSFET can drive a high current load, MBRS340 diode protects from back EMF.

Components Details

  • R1 and R2 SMD 5% 0805
  • FDD8876 SMD Mosfet
  • D1 and D2 SMD Mosfets
  • C1, C2 SMD Ceramic 1210 Capacitor
  • CN1,CN2 Screw Terminals 


  • Supply 12V DC
  • Load 4Amps Max
  • PWM Duty Cycle 0 to 100%
  • Arduino Nano D3-PWM Pin-Connected to Mosfet

About MBRS340 Diode

The Schottky Rectifier employs the Schottky Barrier principle in a large area metal-to-silicon power diode. The Schottky Rectifier’s state-of-the-art geometry features epitaxial construction with oxide passivation and metal overlay contact. It is ideally suited for low voltage, high-frequency rectification, or as freewheeling and polarity protection diodes in surface mount applications where compact size and weight are critical to the system.

  • Small Compact Surface Mountable Package with J-Bend Leads
  • Rectangular Package for Automated Handling
  • Highly Stable Oxide Passivated Junction
  • Excellent Ability to Withstand Reverse Avalanche Energy Transients
  • Guarding for Stress Protection

Reduction Assembly for Camera slider, CNC Router, Automation, 3D Printer Using NEMA23 Stepper Motor and timing Pulley

Reduction Assembly  for Camera slider Using Nema 23 Motor and Timing Pulley

Reduction assembly provides 4 times the torque capacity of NEMA 23 motor by using large size pulley and belt. Its features timing pulley on the main out shaft to drive timing belt for linear motion. The unit has been designed to drive professional camera slider however it can be used in various CNC and motion control applications. The unit consists Sanyo Denki high torque NEMA23 motor, 18 teeth HTD timing pulley at motor side and 72 teeth timing pulley at output shaft which provides 1:4 ratio reduction, output has HTD 5MM 20 teeth pulley for slider belt driver.  This unit can be used with rack pinion, use Pinion at output shaft instead of timing pulley.


Reduction Ratio 1:4
Nema 23 Motor
Timing Belt 3MM HTD 15MM Width

Open Ended Timing Belt at Output 15MM width 5MM HTD

Output Timing Pulley 20 Teeth 15MM HTD M5 Pulley

DC Motor Speed Controller with 2 digit display ( Duty Cycle Display)

The versatile DC motor speed controller project is based on PIC16F1825 microcontroller, its generate PWM pulse and also display the value on 2 digit 7 segment display, duty cycle adjustable 0 to 99 %, Frequency 1Khz, the speed of motor possible with help of two tactile switches.  The board only generate and display the PWM, project required Mosfet on output to drive the motor. Check the circuit diagram for the Mosfet circuit.

Note: Output MOSFET can be used as per current and voltage requirements, it is advisable to use isolated DC solid state relay at the output.

Download Hex Code For This Project

Download Data Sheet Of PIC16F1825

Download PDF Schematic


  • Supply 5V DC
  • Motor supply 12V to 30V DC
  • Frequency 1Khz
  • Duty Cycle 0 to 99%
  • Mosfet is outside of the board

3Amps Adjustable Power Supply Provides 1.2V to 15V DC LM1084-ADJ

Simple power supply circuit provides variable output voltage 1.2V to 15V DC and load current up to 3 Amps, onboard trimmer pot provided to adjust the output voltage. Output capacitor C3, C4 provided for transient response, the circuit can take DC input as well as AC input, maximum DC input 15V DC and AC input 12V AC. LM1084-adj IC is heart of the project.

LM1084-ADJ Data Sheet


  • Output 1.2V to 15V DC
  • Input DC 15V DC
  • Input AC 12V AC
  • Load Current Up to 3Amps

Note : The project also can be used with LM1085-ADJ, LM1086-ADJ, AND LM317-ADJ

Note : Higher input and output volatge possible with few changes, input filter capacitor volatge , higher current bridge rectifier can provide higher current up to 5amps with LM1084-adj. refer data sheet of LM1084-ADJ



The LM1084 is a regulator with a maximum dropout of 1.5 V at 5 A of load current. The device has the same pinout as TI’s industry standard LM317.

Two resistors are required to set the output voltage of the adjustable output voltage version of the LM1084. Fixed output voltage versions integrate the adjust resistors.The LM1084 circuit includes a zener trimmed bandgap reference, current limiting, and thermal shutdown.

Refer to LM1085 for the 3A version, and the LM1086 for the 1.5A version.

5 Phase Stepper Motor Driver Circuit

The  compact 5 Phase stepper driver project can handle motor up to 3.5amps supply 12-30V DC, driver has facility to set the load current, driver provides half stepping and full stepping, and easy to drive with step and direction pulse, trimmer pot provided to set the current,  The SI-7510 is a pre-driver IC for driving 5-phase stepper motors wound in the New Pentagon configuration (driver circuit design patented by Oriental Motor Co., Ltd.). Direct external control of motor driving functions are synchronized by the built-in sequencer to an applied clock input (CL) signal. The SI-7510 drive is implemented with a user-configurable output stage consisting of dual N-channel power MOSFETs. This results in lower thermal resistance and greater efficiency.

Features and Benefits

• Main supply voltage 12v to 24V DC ( Up to 42V Possible with altering Components Read Data sheet)

• Logic Supply Regulator On Board

• External forward and backward motor rotation control via

CW/CCW input

• External selection of 4-phase (full step) and 4-5–phase

(half step) driving via F/H pin

• Output enable/disable control via Enable pin (internal

sequencer function remains active during Disable state,

monitoring the clock input (CL) for automatic sequencing)

• Built-in charge pump circuit for driving external high-side

N-channel MOSFETs of all output phases

• Self-excitation constant current control set by external R-C

circuit time constant on RC input

Balanced Audio Line Driver (Unbalance to Balance Audio Signal Converter) Using DRV135/SSM2142

The Mini board converts unbalance Audio signal into balance audio signal, the project is based on SSM2142 or DRV135 IC which are differential output amplifier that converts a single ended audio signal input to a balanced output pair. This balanced audio driver consists of high-performance op-amps with on-chip precision resistors. They are fully specified for high-performance audio applications and have excellent ac specifications, including low distortion (0.0005% at 1 kHz) and high slew rate (15 V/µs).

The on-chip resistors are laser-trimmed for accurate gain and optimum output common-mode rejection. Wide output voltage swing and high output drive capability allow use in a wide variety of demanding applications. They easily drive the large capacitive loads associated with long audio cables. Used in combination with the INA134 or INA137 differential receivers, they offer a complete solution for transmitting analogue audio signals without degradation.

Note: SSM2142 and DRV135 pin to pin compatible, any of this IC can be used.


  • Supply Dual 15V DC (+/-15V DC)
  • Balanced Output
  • Low Distortion: 0.0005% at f = 1 kHz
  • Wide Output Swing: 17Vrms into 600 Ω
  • High Capacitive Load Drive
  • High Slew Rate: 15 V/µs
  • Low Quiescent Current: ±5.2 mA IC
  • Companion to Audio Differential Line Receivers
  • Header Connector Provided for Audio Signal Input
  • Header Connector for Supply Input
  • Audio Output from XLR Connector
  • Input Aux Audio Signal
  • On-Board Power LED


  • Audio Differential Line Drivers
  • Audio Mix Consoles
  • Distribution Amplifiers
  • Graphic Equalizers
  • Dynamic Range Processors
  • Digital Effects Processors
  • Hi-Fi Audio Equipment’s


  1. Capacitor C5, C10, C7 Non-Polar Capacitors
  2. All Resistors SMD 0805 5%
  3. LED SMD 0805
  4. C1,C3,C7 Electrolytic Capacitors SMD
  5. Output XLR Male Connector
  6. ETH Chassis Ground

Design Requirement

Consider a design with the goal of deferentially transmitting a single ended signal of up to 22.2 dBu through 500 ft of cable with no load at the receiving side. The signal at the end of the cable should have no more than 0.002 per cent of total harmonic distortion plus noise (THD+N) at 10 kHz and less than 0.0005 percent of THD+N for frequencies between 20 Hz and 1 kHz.

The system is required to put out a single-ended signal 0 dB with respect to the input signal and accommodate inputs with a peak to RMS ratios of up to 1.5 for the maximum 22.2 dBu range established above.

The DRV134 and DRV135 were designed for enhanced ac performance. Very low distortion, low noise, and wide bandwidth provide superior performance in high-quality audio applications. Laser-trimmed matched resistors provide optimum output common-mode rejection (typically 68dB), especially when compared to circuits implemented with op-amps and discrete precision resistors. In addition, high slew rate (15 V/μs) and fast settling time (2.5 μs to 0.01%) ensure an excellent dynamic response. The DRV134 and DRV135 have excellent distortion characteristics. As shown in the distortion data provided in

the Typical Characteristics section, THD+Noise is below 0.003% throughout the audio frequency range under various output conditions. Both differential and single-ended modes of operation are shown. In addition, the optional 10μF blocking capacitors used to minimize VOCM errors have virtually no effect on performance. Measurements were taken with an Audio Precision System One (with the internal 80 kHz noise filter

Example Circuit With Balanced Line Receiver

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