Charger Nicad Batere Sederhana

This simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base-emitter voltage of the transistor and the forward voltage drop across the diodes are relatively stable. The charging current is approximately 15mA or 45mA with the switch closed. This suits most 1.5V and 9V rechargeable batteries. The transformer should have a secondary rating of 12V ac at 0.5amp, the primary should be 220/240volts for Europe or 120volts ac for North America.

 
Warning
Please take care with this circuit. Use a voltmeter to observe correct polarity. Nicads can explode if short circuited or connected with the wrong polarity.

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12V to 220V Converter

This DIY 12V to 220V voltage converter is build with CMOS 4047 that is the main component of this small voltage converter that transforms a 12V DC into 220V AC. 4047 is used as a astable mutivibrator, at pins 10 and 11 will have a symmetrical rectangular signal wich is amplified b 2 Darlington transistors and finally reach the secondary coil of mains transformer ( 2x10V / 60VA ).

At the main voltage converter transformer terminals it will be 220V. With the help of P1 the output frequency can be adjusted between 50Hz to 400Hz. Although this is not part of any professional dc ac converters it can be used quite effective on some home appliances.

For more DC to AC voltage converters check the related posts.

Source : http://electroschematics.com/

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