Wednesday, December 18, 2013

Simple 8 Amp Regulated Power supply Circuit Diagram

This Simple 8-Amp Regulated Power supply Circuit Diagram is powered by a transformer operating from 120 Vac on the primary and providing approximately 20 Vac on the primary, and providing approximately 20 Vac on the secondary. Four 10-A diodes with a 100 PIV rating are used in a full-wave bridge rectifier. A 10,000 ^F/36 Vdc capacitor completes the filtering, providing 28 Vdc. 

The dc voltage is fed to the collectors of the Darling-ton connected 2N3055s. Base drive for the pass transistors is from pin 10 of the µ723 through a 200 ohm current limiting resistor, Rl. The reference terminal (pin 6) is tied directly to the non-inverting input of the error amplifier (pin 5), providing 7.15 V for comparison. The inverting input to the error amplifier (pin 4) is fed from the center arm of a 10 k ohm potentiometer connected across the output of the supply.

Simple 8-Amp Regulated Power supply Circuit Diagram

Simple 8-Amp Regulated Power supply Circuit Diagram

This control is set for the desired output voltage of 13.8 V. Compensation of the error amplifier is accomplished with a 500 pF capacitor connected from pin 13 to pin 4. If the power supply should exceed 8 A or develop a short circuit, the µ723 regulator will bias the transistors to cutoff and the output voltage will drop to near zero until the short circuit condition is corrected.
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Tuesday, December 17, 2013

Treble Tone Control

The treble control works in a similar manner as the bass control elsewhere in this site, but contains several modifications, of course. One of these is the series network C1-C2– R1– R1 1. The d.c. operating point of IC3 is set with resistors R12 and R13. To ensure that these resistors do not (adversely) affect the control characteristics, they are coupled to the junction of R9 and R1 0. In this way they only affect the low-frequency noise and the load of the opamp. Their value of 10 kΩ is a reasonable compromise. The functions of switches S1– S3 are identical to those of their counterparts in the bass tone control; their influence is seen clearly in the characteristics.

Treble Tone Control Circuit diagram:

Treble_Tone_Control_Circuit_Diagramw

Good symmetry between the left-hand and right-hand channels is obtained by the use of 1% versions of R1– R1 3 and C1, C2. The value of resistors R2– R1 0 is purposely different from that of their counterparts in the bass tone control. In the present circuit, the control range starts above 20 kHz. To make sure that a control range of 1 0 dB is available at 20 kHz, the nominal amplification is 3.5 (11 dB ). The control circuit draws a current of about ±10 mA.

Source :  http://www.ecircuitslab.com/2011/06/treble-tone-control.html
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Monday, December 16, 2013

This kind of cell phone jammer has the similar appearance to the cell phone

 This kind of high-level cell phone jammer can be utilized to prevent the related personnel from using the cell phone or some other wireless signal devices like the wireless bug and so on.The size and weight of cell phone jammer should be listed in the product description
First, the subsidy model. According to the fine degree of screening the target population, develop different advertising costs. Advertising, accepting the ad gift bill, accept an advertising messages presented 1 to 2 cents a day, up to accept 10, unwilling to accept, you can reply to Close. Member model. Can be used for some businesses to provide services for members and potential clients, such as large supermarkets regularly to Member discount product information and promotional activities, and interactive activities. Industry solutions for supermarkets, appliance stores, clubs and other membership-based businesses to provide phone-based member services, such as supermarkets printing goods MMS, home appliances shopping malls buy concessions. Some high-level cell phone jammer can be used to detect or inspect almost all cell phone signals or almost all wireless signals.
The third is the custom mode. Advertising information in accordance with the classification of life, finance, real estate, catering, and forms of advertising evolve into the information class information, such as sports equipment sports enthusiasts SMS products made user voluntarily free custom. This mode of operation is to pay attention to the users to receive degrees, advertising information, improve customer receiving the degree, and gradually develop their habit of receiving an initial advertising content should be strictly controlled, the focus on developing a good reputation, practical product advertising, such as automotive, food and beverage entertainment, but also concerned about the scale and sophistication of the database, only the formation of large-scale users of analysis, in order to form a media advantage. Interactive mode. Create content, sub-categories of advertising database forwarding platform, the user registered as a member.  At present, Guangdong Mobile, Shanghai Mobile has been around mobile media advertising, design E Armco "benefit" and other mobile media advertising brand, Shandong Mobile is launching a mobile media advertising planning and promotional efforts, you can learn from their experience, brand planning, but also do product line and brand packaging, and establish a mature product line, one by one to promote.  cell phone jammer is through detecting and inspecting the cell phone signal emitted by the cell phone. This kind of cell phone jammer has the similar appearance to the cell phone.
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Monday, September 2, 2013

1W Audio Amplifier Using NCP2830

This 1w audio amplifier circuit is designed using NCP2830 audio IC manufactured by ON Semiconductor.This audio power amplifier ic designed for portable communication device applications and require few external electronic components.

1W Audio Amplifier Circuit using NCP2830 


NCP2830 is capable to provide 1W continuous output power in 8 ohms load.NCP2830 audio power amplifier main features are : high quality audio (THD+N = 0.04%) , low noise: SNR up to 100 dB, overall system efficiency optimization: up to 89% , Superior PSRR (−88 dB): Direct Connection to Battery , Very Low Quiescent Current 7 mA , Optimized PWM Output Stage: Filterless Capability , Selectable gain of 2 V/V or 4 V/V .
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