Schematic | Circuit guide | Manual Wiring diagram | Electronic
Showing posts with label booster. Show all posts
Showing posts with label booster. Show all posts

Car Alarm Sound Booster

Posted by Unknown Friday, December 27, 2013 0 comments
For car alarms, emphasis should be put on hearing the audible alert and identifying it as belonging to your wheels. Unfortunately, modern car alarm systems seem to have more or less the same alarm sound especially if they are from the same brand. Also, to comply with legal noise restrictions, the alarm sound is not always loud enough to be heard if the car is parked down the road.

Simple Car Alarm Sound Booster Circuit Diagram
Simple Car Alarm Sound Booster-Circuit Diagram

The circuit shown here is designed to help boost the alarm sound by also activating the cars horn(s) when the alarm goes off. lnternally the car alarm system often provides a signal that activates the (optional) engine immobilizer and/or volume (ultrasound) sensors. This signal usually goes Low upon sys-tem triggering and high again when the alarm system is deactivated.

The alarm activation signal is fed to the circuit through Dl . When in idle state, T1 s gate is High and consequently the FET conducts,  keeping  power  FET T2 firmly switched off. When the  system gets an  active  low signal, T1  switches  off allowing  timing  capacitor C2 to charge  via  R2. About 15 seconds later, when the voltage across C2 is high enough, T2 starts to conduct and relay RE1 is energized. This, in turn, provides the required path for the lights flashing signal to energize RE2 and feed battery power to the cars horn(s).

When the alarm system is turned off the activation signal returns to High. T1 starts to conduct and rapidly discharges C2 via R3. T2 is then cut off and REl is de-energized. Diode D2 suppresses back EMF from REl. The circuit draws less than 2 mA when idling. When activated the circuits current consumption is virtually that of the RE1 coil. RE1 is any simple SPST or SPDT relay, capable of switching  about 0.5 A (at 12 V). The coil rating is for 12 VDC and a current requirement as low as you can find. Fuse F1 should be a slow blow type and rated about twice RE1s coil current.

The B5.170 in position T2 can sink a continuous current of about 0.5  A. However, a value of 1.2 A pulsed is specified by Fairchild  for their devices. To keep the FETs d-s current due to C2 discharging within safe limits, R2 may be increased, C2 decreased and R3 increased, all proportionally. A factor of 2 will keep the FET out of harms way with maybe a slight change in the 15-second delay and the sensitivity of the circuit. C1 is used as a smoothing capacitor and F2 should be rated in accordance with the horn(s) maximum current draw.

Caution. The installation and use of this circuit may be subject to legal restrictions in your country, state or area.

Source:    http://www.ecircuitslab.com/2012/06/simple-car-alarm-sound-booster.html

The material test of cell phone booster

Posted by Unknown Monday, December 16, 2013 0 comments
The material test of cell phone booster cannot be cancelled
Further established the worlds largest cell phone users status. Industrial scale, concentration increased as of April 2007, 41 new cell phone companies, including 11 foreign-invested enterprises, Chinese enterprises to 30, with production capacity of about 140 million while the new cell phone manufacturers in the low-end products based mainly on the Chinese market, the annual demand of about 60 million to 100 million units, made in China to exceed demand and production companies to expand the number of cell phone production growth will further exacerbate the market competition increasingly fierce competitive environment has led to an overall decline in industry profits, loss of business and the amount is increasing. cell phone booster can work continuously for a long time. On the other hand, the Chinese cell phone industry to further expand the industrial scale, while also further enhance the industrial concentration which Nokia, Motorola, Samsung, Sony Ericsson, Bird, Lenovo, and Amoi top ten companies account for almost the total production of all 80% of the industry, including Nokia, Motorola, Sony Ericsson and Samsung, the market share of 81.96 percent, the domestic cell phone market share of SMEs is very limited. 72. handset industry value chain structure of the cell phone industry value chain structure divided into three two components: the upper reaches of cell phone R & D, design and component suppliers, midstream and downstream cell phone handset manufacturers brand marketers, operators in the mobile industry on a technical level, Chinas cell phone industry is still in catch-up phase, the total production level in the cell phone Chinese cell phone industry in rapid growth stage. The company only takes responsibility of changing a new cell phone booster or repairing cell phone booster .
Chinese cell phone industry cluster is still in the global value chain under the low value-added chain. Handsets needed for the production of most of the active and passive, body parts (only about 30% of production costs) can be made, but not yet fully grasp the industry core technology and key components of the production technology, and small-scale enterprises, SMEs accounted for 92.61% of the proportion of overall competitiveness. Chinese cell phone industry structure shows structural characteristics of olive shape: the upper reaches of the lack of core technology and key components industry production technology; River is gradually assembled a strong, general parts production capacity; and downstream of brand management, logistics are still weak. Upstream: cell phone design platform (chip module). Overall, Chinas cell phone industry cluster is still in the low-value-added chain of production processes and generally supporting the production of parts gathering stage of development.