Free electronic circuit design and schematic diagram
If you need +-15 Volts supply and you have only a standard 12V AC transformer, don’t be hurry to buy a new one with center tap, you can use your old transformer! The schematic diagram of this circuit is shown in the figure below. The voltage before entering the regulator IC 7815 and 7915 might reach 24 volts, if there […]
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Many cheap battery chargers usually assume that charging the battery slowly is OK although the battery is already full of charges. All they do is usually charging the battery with constant current no matter if the battery is almost completely discharged or has been fully charged. Off course the battery wouldn’t be damaged immediately after few charging cycles, but actually […]
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Don’t worry if you need a symmetric power supply and you don’t have a center tapped transformer. The circuit below solve your problem. You can see the second bridge diode is powered via capacitor decoupling, so it’s DC isolated. Because it’s DC isolated, we can connect the ground together to form a symmetric supply. Because the second rectifier is powered […]
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It seems that center tapped transformer with a bridge diode is common solution to provide symmetric power supply, but we can actually do it with simpler solution, using a voltage doubler – rectifier diodes. You can see this simple circuit in the figure. The capacitor need to be large because the rectifying is half wave, so you can avoid power […]
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Tired replacing your power supply fuses, or it cost too much because too often to blow? Use this electronic fuse and your life would be easier. It is good for your new power supply design, or you can just add it to your old power supply unit. This fuse has real fast response because it works based on solid state […]
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In application that demand for high current, Nicad (NiCd) rechargeable battery still has the unbeatable performance compared to NiMH and Lithium battery. The charger circuit here is smart in the way it handle the wrong polarity of the battery placement. The core of this battery charger circuit is the Q2, configured a constant current source for the battery. LED D3 […]
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