Free electronic circuit design and schematic diagram
Random noise source is often needed in testing many type of electronic systems such as filter, audio, or RF communication. The circuit presented here generates an RMS amplitude regulated noise source with selectable bandwidth. With 1 KHz to 5 MHz decade ranges selectable bandwidth and 300mV RMS output, this noise generator is suitable for wide range of application. Noise is […]
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Fast peak detector requires special amplifier features. The output stage must have high slew rate to keep up with the intermediate stages of the amplifier. This condition causes either a long overload or DC accuracy errors. The amplifier must deliver large currents into the capacitive load of the detector to maintain a high slew rate of at the output. Other […]
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To avoid exceeding luminance reference level standard or to avoid exceeding the input range of digitizer (ADC), video signal is often needed to be limited. The simple way to do this is by hard limiting the signal in the positive direction (white peak clipping), but this method completely destroy all information contained in the clipped region. The better way to […]
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A laser diode driver can be implemented using voltage-controlled current source. This simple linear laser diode driver gives cleaner drive current than a switched (PWM) drivers. Here is the schematic diagram of the circuit: A Howland current pump with a current booster is used as the basic of this laser diode driver. Q1 is used as the current booster on […]
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All of the necessary circuitry to optimally control the charge and hold cycle for sealed lead acid battery can be implemented using UC2906 series of battery charger controllers. These integrated circuits monitor and control both the output voltage and current of the charger through three separate charge states; a high current bulk-charge state, a controlled over-charge, and a precision float-charge, […]
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Stepper motor gives a simple, low cost, and accurate position control. Stepper motor can be driven by circuit mounted close to the motor, and controlled by a remote control circuit through long cable. The interesting thing of this circuit is that the power for both motor and the driver circuit is carried over two wires, the same wires that carry […]
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Closed Loop Motor Control Closed loop (servo) control is used to make a constant speed motor control. Constant speed means that the speed of the motor will be kept constant although the load is change, or even when the electric supply voltage is also changed. The circuit maintain the speed at a constant value by sensing the actual speed using […]
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