Showing posts with label box. Show all posts
Showing posts with label box. Show all posts

Thursday, January 16, 2014

Automotive Ignition Coil Buzz Box

This picture is a circuit for a buzz coil using a standard car battery to create. Dual timer IC 556 is used to set the frequency and the duty cycle of the coil current to be determined. One of the timer is used as an oscillator for generating the rectangular waveform 200 Hz to control (IRF740 MOSFET), while the second timer is stopped and the oscillator switching points are opened and closed (closed = a). The result is a steady stream of sparks of the ignition coil a distance of about 5 milliseconds, while the switching points are closed. Operation: Pin 8 and 12 the trigger inputs, and a timer which are driven by the points and an inverted signal of the clock output (pin 9) to produce.

Automotive Ignition Coil Buzz Box Circuit Diagram


When the pin 9 is grounded points high, and vice versa. The signal on pin 9 controls the reset line (pin 4) of the second timer and keeps the output at pin 5 is low, while pin 4 and pin 8 is low and 12 high (still open). The 15K and 47K resistors and capacitors are 0.33uF synchronization components that the frequency and duty cycle of the second clock, which is about 4 milliseconds to 2 milliseconds apart to secure positive and negative. During the time interval is positive, the doors are always high MOSFET causing the coil to the current height of about 4 amps. This equates to approximately 80 milli joules of energy in the coil is released in the spark plug when the clock output (pin 5) moves on the ground, turn off the MOSFET. A zener diode 12 volts is placed on the node 10 and 27 ohms for the MOSFET gate input is above or below 12 volts -0.7 volts. A Zener diode 200 volts / 5 W used for the drain voltage of the MOSFET 200 and limit the useful life of the spark to expand.

The circuit must operate reliably with a jumper, but the circuit operation with no load applied (the son of candle down, etc.) may cause a malfunction, because most of the energy absorbed by the Zener. You can also use a transient voltage suppressor (TVS) as 1.5KE300A 1.5KE200A or instead of the zener. This is probably a good hand, but difficult to obtain.
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Saturday, September 14, 2013

Subwoofer Speaker box design

The order of 4 or sealed rear chamber bandpass system is essentially a system of watertight enclosures with the addition of an acoustic filter for the driver. The resulting system usually provides a lower cut-off frequency, the compromise that a larger case. The space can be reduced by two drivers in isobaric configuration.

4th-order bandpass systems generally show better able to handle the functions that the other major systems are considered. The transient response and is second only to the sealed enclosure systems, making it a good choice for subwoofer applications.

Subwoofer Speaker box design
Subwoofer Speaker box design

Since all output 4th order bandpass system is via the port, the largest diameter possible for the port area should be used to minimize noise from the port. The ports must be incinerated where possible, for the same reasons.

The 4th order bandpass system rarely allows a perfect bandpass response - there is usually an out-of-band noise present in the production. A notch filter can be used simply to reduce the noise as audible. Otherwise, a lowpass filter used in series with the driver, but the in-band response system may be affected if this approach is taken.

As the speaker sound 4th order band pass issued by the openings or ports on the port side of the box, the port noise inevitable.

This unwanted noise can be minimized by a notch filter and the largest diameter possible for the port of the area should definitely be used. Another option is to burn the ports of the 4th order bandpass room as this will certainly help to reduce unwanted extra from the subwoofer.
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