VOLTAGE DOUBLER A voltage higher than the supply can be created by a "Charge-Pump" circuit created with a 555, diodes and capacitors as shown in the following circuit. The output will deliver about 50mA
This circuit drives a 3x3x3 cube consisting of 27 white LEDs. The 4020 IC is a 14 stage binary counter and we have used 9 outputs. Each output drives 3 white LEDs in series and we have omitted a dropper resistor as the chip can only deliver a maximum of 15mA per output. The 4020 produces 512 different patterns before the sequence repeats and you have to build the project to see the effects it produces on the 3D cube.
:: برچسبها:
3x3x3 CUBE ,
:: بازدید از این مطلب : 221
This circuit confuses the infra-red receiver in a TV. It produces a constant signal that interferes with the signal from a remote control and prevents the TV detecting a channel-change or any other command. This allows you to watch your own program without anyone changing the channel !! The circuit is adjusted to produce a 38kHz signal. The IR diode is called an Infra-red transmitting Diode or IR emitter diode to distinguish it from a receiving diode, called an IR receiver or IR receiving diode. (A Photo diode is a receiving diode). There are so many IR emitters that we cannot put a generic number on the circuit to represent the type of diode. Some types include: CY85G, LD271, CQY37N(45¢), INF3850, INF3880, INF3940 (30¢). The current through the IR LED is limited to 100mA by the inclusion of the two 1N4148 diodes, as these form a constant-current arrangement when combined with the transistor and 5R6 resistor.
The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply. The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series.
This is a game for two players. Player 1 presses the START button. This resets the 4026 counter chip and starts the 555 oscillator. The 555 produces 10 pulses per second and these are counted by the 4026 chip and displayed on the 7-Segment display. The second player is required to press the STOP button. This freezes the display by activating the Clock Inhibit line of the 4026 (pin 2). Two time-delay circuits are included. The first activates the 555 by charging a 10u electrolytic and at the same time delivering a (high) pulse to the 4026 chip to reset it. The second timer freezes the count on the display (by raising the voltage on pin 2) so it can be read
This circuit produces 10 different tones and by selecting suitable values to change the voltage on pin 5, the result can be quite pleasing. Note: the two unused outputs of the 4017 produce a tone equal to that produced by the 555 when pin 5 has no external control voltage
:: برچسبها:
MUSIC BOX ,
:: بازدید از این مطلب : 191
The 555 will activate a relay. When pins 2 and 6 are connected as an input, the chip requires only about 1uA to activate the output. This is equivalent to a gain of about 200,000,000 (200 million) and represents about 4 stages of amplification via transistors. In the first circuit, the output will be opposite to the input. The relay can be connected "high" or "low" as show in the second diagram. One point to note: The input must be higher than 2/3V for the output to be low and below 1/3V for the output to be high. This is called HYSTERESIS and prevents any noise on the input creating "relay chatter." NEGATIVE
This circuit produces a tone above the human audible range and this is supposed to keep the mosquitoes away. You need a piezo diaphragm that will respond to 15kHz and these are very difficult to find. to
The output is LOW at start-up due to the capacitor on pin 4. When the mercury switch closes, the output goes HIGH and remains HIGH until the reset button is pressed. This circuit is called a LATCH. See Latch circuit and Memory Cell above
This is the circuit for Dr. Hulda Clark's Zapper, designed in 2003. The frequency is approximately 30kHz positive offset square wave. It has a red LED light that lights up when the unit is on. Perfect for regular zapping, extended zapping and other Hulda Clark related experiments. This device is used to cure, treat and prevent any disease. It will cure anything. Simply hold the two probes (one in each hand) for 5-10 minutes then rest for 20 minutes, then repeat two more times. Do this each day and you will be cured. Here is the .pdf of her book: A Cure For All Diseases. Website: http://clarktestimonials.com/ Hundreds of people have been cured of everything from herpes to AIDS. On the other side of the coin is the claim that Dr Hulda Clark is a complete quack. Here is a website called: Quackwatch. The second diagram shows the two copper tubes and the circuit in a plastic box. I am still at a loss to see how any energy can transfer from this quack machine, through the skin (50k skin resistance and 9v supply) and zap a bug in your intestine. It's a bit like saying I will kill all the mice in a haystack by stabbing the stack with a needle.