Free electronic circuit design and schematic diagram
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 low impedance quadrature output […]
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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 “constant-current” mode. Here is the […]
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This SMPS AC-DC converter gives good efficiency. Test data shows efficiency of 83.2% at 115 Vac input and 6A output current, and 85.4% at 230 Vac input and 6A output current. Moreover, the input voltage range is universal, accommodating 92 to 276 Vac variation with only 24 mV change in the output voltage. Here is the schematic diagram of the […]
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Crystal Colpitts oscillator can be implemented using a transistor and a parallel mode crystal. Here is the schematic diagram of the circuit: In this circuit, the crystal acts as an inductance. A large value capacitive divider is used between gate, source, and ground, and a small series capacitor is placed in the crystal circuit. You should choose the components values […]
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More efficient lead acid battery charger can be implemented using switch mode circuit. A switch mode for lead acid battery charger can be constructed using bq24105 battery charger controller. The bq24105 was originally designed to charge single-, two- or three-cell Li-ion and Li-polymer battery packs. Its features doesn’t include the control for lead acid battery charger termination. Here we add […]
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As the price of security camera going down, installing the camera in the shop, office, or even in home becomes economically feasible. Providing a dedicated monitor for every installed camera is not efficient, and your CRT monitor might suffer phosphor burn if it used to display static image from only one camera. To display 1, 2, 3, or 4 cameras […]
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This power factor controller accept voltage from 90 to 268 Vac, that’s why we call it power factor controller with universal input, since any standards of mains supply in almost any country would fall within that range. This power factor controller is capable of handling up to 450W load. Here is the schematic diagram of the power factor controller circuit: […]
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