Free Circuit Diagram

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 [...]

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 [...]

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, [...]

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 [...]

Bubba oscillator is another example of phase shift oscillator. The Bubba oscillator takes the advantage of quad op-amp package to get 45 degree phase shift for each section. The result is excellent d(phase)/d(t) to get very low frequency drift. Here is the schematic diagram of the circuit:

Each RC section give 45 degree phase shift. A [...]

Thermoelectric cooler (TEC) or Peltier cooler is becoming popular because of its robustness and maintenance free characteristic. Here is one example of a linear thermoelectric cooler (TEC) driver circuit. This driver  is capable of delivering ±2A into a TEC. This circuit operates on a single +5V supply and drives the TEC in the most preferred [...]