Wiring & diagram Info

In most WCs with an extractor the fan is connected to the lighting schema and is switched on and off either in sympathy with the light or with a short delay. Since toilets are sometimes used for washing the hands or just for a quick look in the mirror, it is not always necessary to change the air in the smallest room in the house. The following schema automatically determines whether there really is any need to run the fan and reacts appropriately. No odour sensor is needed: we just employ a small contact that detects when and for how long the toilet seat lid is lifted.

 On-Demand WC Fan Using 555 schema diagram

If the seat lid is left up for at least some presettable minimum time t1, the fan is set running for another presettable time t2. In the example shown the contact is made using a small magnet on the lid and a reed switch mounted on the cistern. The rest is straightforward: IC2, the familiar 555, forms a timer whose period can be adjusted up to approximately 10 to 12 minutes using P2. This determines the fan running time. There are three CMOS NAND gates (type 4093) between the reed switch and the timer input which generate the required trigger signal. When the lid is in the ‘up’ position the reed switch is closed.

Capacitor C1 charges through P1 until it reaches the point where the output of IC1a switches from logic 1 to logic 0. The output of IC1b then goes to logic 1. The edge of the 0-1 transition, passed through the RC network formed by C2 and R2, results in the output of IC1c going to logic 0 for a second. This is taken to the trigger input on pin 2 of timer IC2, which in turn switches on the relay which causes the fan to run for the period of time determined by P2. The schema is powered from a small transformer with a secondary winding delivering between approximately 8 V and 10 V. Do not forget to include a suitable fuse on the primary side.

The schema around IC1b and IC1c ensures that the fan does not run continuously if the toilet seat lid is left up for an extended period. The time constant of P1 and C1 is set so that the fan does not run as a result of lavatorial transactions of a more minor nature, where the lid is opened and then closed shortly afterwards, before C1 has a chance to charge sufficiently to trigger the schema.

LEDs are becoming increasingly popular in many lighting applications. White LEDs are now common in torches.

Simple LED Torch Circuit Diagram

Here’s a simple and economical LED torch that operates off two 1.5V cells. For a white LED, the forward conduction voltage and the forward current are 3.6V and 20 mA, respectively. Capacitor C1, the transistor, and the transformer form a self-oscillating DC-DC converter. The transformer boosts the input battery voltage and supplies a high voltage to the white LEDs. Diode D1 and smoothing capacitor C2 supply the high voltage to the LED chain via resistor R2.

The light intensity is affected by the input battery voltage. As the transformer is not readily available in the market, you may need to build it yourself. The transformer windings also affect the light intensity. The transformer coil is wound on a 4mm thick ferrite toroid having 13mm outer diameter and 6mm inner diameter.

Primary windings comprise 4 turns and secondary windings 55 turns of 36SWG copper-enamelled wire on toroid transformer core as shown on the right side in the figure. For the long life of 1.5V cells, keep switch S1 in ‘on’ position only when the torch is in use.

     This is the circuit diagram of a fully transistorized sub woofer amplifier that can produce an output of 100W.There are seven transistors including four in the output stage. The transistors Q1 and Q2 form the preamplifier stage. Transistors Q4 to Q7 form the output stage. Since no ICs are used the circuit is very robust and can be easily assembled on a general purpose PCB.

Bored of joking with capacitors? Then its time for you to maneuver on to super-capacitors. These have huge storage capabilities. during this article you may conclude the way to build atiny low LED flashlight using supercapacitors.

The most disadvantage of capacitors is their giant voltage drop. For this project, a minimum voltage of two volts is needed to light-weight the LED. As a result, the “Joule Thief” style would be incorporated here. Using this, a AA battery is used to light-weight an LED until its fully discharged.
 during this case, a supercapacitor would be taking the place of the battery. Here an LED is employed to perform the operate of a diode. This ensures that theres sufficient voltage across the LED.

 the necessities of the project are listed below:
White LED
Super capacitor (10F, 2.7 V)
Transistor
Torus
1 k ohm resistor
Wires
Breadboard
The torus and therefore the transistor used here comes from an energy-saving lamp HS. Care ought to be taken whereas removing this from the lamp as a breakage may lead to the discharge of the mercury vapors. A lamp load along side a USB port is added to the schema. This makes it compatible with a computer or a automotive radio.

A couple of precautions got to be taken whereas constructing the schema. The USB port mustnt be supplied with excess power. The capacitor doesnt stand up to a high voltage and hence a zener diode is connected in parallel to handle the high voltage. The diode protects the capacitor when the voltage exceeds an explicit price.