Menghitung nilai resistor dengan bantuan tabel
Thursday, January 24, 2013
This AC motor speed controller can handle most universal type (brushed)
AC motors and other loads up to about 250W. It works in much the same
was a light dimmer circuit; by chopping part of the AC waveform off to
effectively control voltage. Because of this functionality, the circuit
will work for a wide variety of loads including incandescent light
bulbs, heating elements, brushed AC motors and some transformers. The
circuit tries to maintain a constant motor speed regardless of load so
it is also ideal for power tools. Note that the circuit can only control
brushed AC motors. Inductive motors require a variable frequency
Tuesday, January 22, 2013
Monday, July 23, 2012
This IR Remote extender can increase the range of most simple ir remote (those operating on a 40KHz modulation) a signivicant distance.In use ,the remote is pointed toward the detector on the circuit,and a button is pressed.The sharp IR detector then decodes the 40KHz modulated signal into a series of pulse,which trigger a 555 timer.The 555 outputs pulses which are re-modulated and used to drive an IR LED.The circuit is excellent for use in a large room like a presentation hall where a typical IR remote is a bit weak .By extending the wires to the output LED(using shielded cable) you can control a device where line of sight isn't avalaible (such as a wall full of TVS in another room).
Sunday, July 22, 2012
This 40 w Flourescent lamp inverter allows you to run 40 w flourescent tubes from any 12 v source capable of delivering 3A.This is a basically a large version of the 12 v DC flourescent lamp driver and can be used to light regular or blacklight tubes.
Posted by Kratos at 7:20 AM
Here it is,it uses a normal 120 to 6v stepdown transformer in reverse to step 12v to about 350v to drive a lamp without the need to warm the fiolaments.
Friday, May 4, 2012
This circuit creates a stunning display of the "magic" of magnetism by suspending a small metal object in mid air. Using an electromagnet, photo sensor and closed loop control, small and light metal objects can be floated just underneath the magnet, enclosed in a decorative arch. "No strings" are easily demonstrated by the ability to pick the metal object out of the air and place it back under the magnet at will. With the object floating about 1/4" under the magnet (exact distance will depend on the weight of the object), an LED and photo transistor arrangement let a feedback circuit know it's position. The circuit controls current to an electromagnet to maintain an equilibrium between the force of the magnet and gravity. Thus, the object floats. Impart a bit of a spin to the object and momentum will carry it for quite a long time as the only friction working against it is between the object and the air.