Tag Archives: DC

50V – 10A Bidirectional DC Motor Driver Using A3941

This tiny board designed to drive bidirectional DC brushed motor of large current. DC supply is up to 50V DC. A3941 gate driver IC and 4X N Channel Mosfet IRLR024 used as H-Bridge. The project can handle a load up to 10Amps. Screw terminals provided to connect load and load supply, 9 Pin header connector provided for easy interface with micro-controller. On board shunt resistor provides current feedback.

The A3941 is a full-bridge controller for use with external N-channel power MOSFETs and is specifically designed for automotive applications with high-power inductive loads, such as brush DC motors. A unique charge pump regulator provides full (>10 V) gate drive for battery voltages down to 7 V and allows the A3941 to operate with a reduced gate drive, down to 5.5 V. A bootstrap capacitor is used to provide the above-battery supply voltage required for N-channel MOSFETs. An internal charge pump for the high-side drive allows DC (100% duty cycle) operation.

50V – 10A Bidirectional DC Motor Driver Using A3941 – [Link]

New current sensors have no magnetic circuits

Clemens Valens @ elektormagazine.com discuss about LEM’s new current sensors which do not use the Hall effect make the measurement. Instead they integrate conductors for gradient measurement and provide immunity against the external fields. He writes:

Here are some new integrated circuit transducers for AC and DC isolated current measurement up to 300 KHz that offer full isolation, despite their small size, by integrating the primary conductor for nominal current measurements of up to 30 A. The transducers are mounted directly onto a printed circuit board as SO8 or SO16 SMT devices and support overload currents up to 200 A peak for short durations (1 ms).

New current sensors have no magnetic circuits – [Link]

A DC Motor Controller with Control Leds

Boris Landoni writes about a new open source project a DC motor controller with control LEDs:

The circuit board we are presenting this time is based on the dual-bridge driver L298N, in a traditionally mounted version in a Multiwatt container with 15 staggered pins; it has two terminal blocks for attaching to DC motors or the coils of a bipolar stepper motor and a terminal block for powering logics and motors. Each of the two output channels of the circuit can provide a maximum current of 2 A, which is enough to drive two 2 A direct current motors or a bipolar stepper motor absorbing 2 A per phase.

A DC Motor Controller with Control Leds – [Link]

Control a stepper motor using Raspberry Pi

Here is a nice tutorial @ raspberrypi.org on how to control a DC motor using Python.

In this guide, you’ll be controlling two motors from your Raspberry Pi using Python on the desktop. First, it’s best just to learn how to control the motor. Then, once you have it working, you could easily use your code to drive a Raspberry Pi-powered robot by detaching the monitor, mouse, and keyboard and building a robot around a chassis.

Control a stepper motor using Raspberry Pi – [Link]

Sensing current on the high side

Michael Dunn @ edn.com writes:

At their heart, the majority of DC current sense circuits start with a resistance in a supply line (though magnetic field sensing is a good alternative, especially in higher-current scenarios). One simply measures the voltage drop across the resistor and scales it as desired to read current (E = I × R (if I didn’t include this, someone would complain)). If the sense resistor is in the ground leg, then the solution is a simple op-amp circuit. Everything stays referenced to ground, and you only have to be careful about small voltage drops in the ground layout.

Sensing current on the high side – [Link]

Low-cost current monitor tracks high dc currents


Susanne Nell @ edn.com has a design idea on how to measure high dc currents.

To measure high levels of direct current for overload detection and protection, designers frequently use either a current-shunt resistor or a toroidal core and Hall-effect magnetic-field sensor. Both methods suffer from drawbacks. For example, measuring 20A with a 10-mΩ resistor dissipates 4W of power as waste heat. The Hall-effect sensor delivers accurate measurements and wastes little power, but it’s an expensive approach to simple current monitoring.

Low-cost current monitor tracks high dc currents – [Link]

Charge-pump topology doubles voltage


has designed a circuit that is able to double the input voltage and breaks DC path.

I once needed a voltage doubler circuit with no DC leakage path between input and output, and ended up devising this unusual 556- (dual 555 timer) based circuit with a “floating” voltage output.

Charge-pump topology doubles voltage – [Link]

Temperature controlled Fan


Ahmad Al-Shalabi and Bassma Karbouj show us how to control a DC fan using easy to find components. The fan works when temperature reach into pre-specified threshold.

The purpose of this project is creating a cooling system by controlling in a DC fan in a simple way without using Microcontrollers or Arduino but by using electronic components that it’s very simple and available. The DC fan controlling achieved by a Thermistor and which is a type of resistor whose resistance is dependent on temperature. there is two type of thermistor that is NTC ” Negative Temperature Coefficient” , PTC ” Positive Temperature Coefficient “

Temperature controlled Fan – [Link]

9 VDC Regulated Power Supply


Tiny low current 9 VDC Regulated Power supply designed around bipolar transistor and zener diode. The circuit is known as series voltage regulator or emitter follower voltage regulator. The unregulated supply fed to input and the circuit regulate the voltage and provide constant 9V DC, 250mA. The zener diode provides the reference voltage to the base of the transistor. This is very suitable power supply for small projects as it can provide any supply output by changing just the zener diode.

Other output voltage can be obtained by changing the zener diode

Output Voltage Formula Vout=Vz-VBe

Vz=Zenner diode Voltage, VBe=0.7V

9 VDC Regulated Power Supply – [Link]

Build a Cloud-Connected ESP8266 Power Meter


Measure the DC power consumption of your devices on the cloud @ adafruit.com

Controlling the electrical consumption in your home is one of the most important thing you can do, both because of environmental concerns & to reduce the electricity bill at the end of the month. There are countless of electrical power meters out there, but in this guide, I’ll show you how to build your own, and to use the ESP8266 feather board to measure how much power a single device is using. Note that this guide is about measuring power for DC (Direct Current) devices only.

Build a Cloud-Connected ESP8266 Power Meter – [Link]