AM Radio Circuits

AM radio began with the first, experimental broadcast on Christmas Eve of 1906 by Canadian experimenter Reginald Fessenden, and was used for small-scale voice and music broadcasts up until World War I. AM radio technology is simpler than Frequency Modulated (FM) radio, Digital Audio Broadcast (DAB), Satellite Radio or HD (digital) Radio. An AM receiver detects amplitude variations in the radio waves at a particular frequency. It then amplifies changes in the signal voltage to drive a loudspeaker or earphones.

The earliest crystal radio receivers used a crystal diode detector with no a

mplification. As a result, many broadcast stations are required as a condition of license to reduce their broadcasting power significantly (or use directional antennas) after sunset, or even to suspend broadcasting entirely during nighttime hours. Medium-wave and short-wave radio signals act differently during daytime and nighttime. However, in the late 1960s and 1970s, top 40 rock and roll stations in the US and Canada such as WABC and CHUM transmitted highly processed and extended audio to 11 kHz, successfully attracting huge audiences. Early experiments with stereo AM radio involved two separate stations (both AM or sometimes one AM and one FM) broadcasting the left and right audio channels.

Because of its susceptibility to atmospheric and electrical interference, AM broadcasting now attracts mainly talk radio and news programming, while music radio and public radio mostly shifted to FM broadcasting in the late 1970s. This system was not very practical, as it required the listener to use two separate radios. Synchronization was problematic, often resulting in "ping-pong" effects between the two channels. Reception was also likely to be different between the two stations, and many listeners used mismatching models of receivers.

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Build a 3000W Stereo Power Amplifier Circuit Diagram

How to Build a 3000W Stereo Power Amplifier Circuit Diagram? Lets start first we define 3000wstereo power amplifier circuit diagram this circuit has a power output of up to 1500W RMS power amplifier circuit is often used to power sound systems spelunker for outdor. In the final image can be seen a series of power amplifiers using 10 sets of power transistors for the ending. This power amplifier circuit using a transistor amplifier from the front, signal splitter, driver and power amplifier. Current consumption required is quite large power amplifier that is 15-20 A 1500W power amplifier circuits for this. Supply voltage needed by the power of this amplifier is the optimal working order symmetrical 130VDC (130VDC-130VDC ground). 1500W amplifier circuit below is a picture series of mono, stereo if you want to make it necessary to make two copies of the circuit. For more details can be viewed directly image the following 1500W power amplifier circuit. The series of High Power Amplifier 15

Solid State Switch For Dc Operated Gadgets

This solid state DC switch can be assembled using just three transistors and some passive components. It can be used to switch on one gadget while switching off the second gadget with momentary operation of switch. To reverse the operation, you just have to momentarily depress another switch. The circuit operates over 6V-15V DC supply voltage. It uses positive feedback from transistor T2 to transistor T1 to keep this transistor pair in latched state (on/ off), while the state of the third transistor stage is the complement of transistor T2’s conduction state. Initially when switch S3 is closed, both transistors T1 and T2 are off, as no forward bias is available to these, while the base of transistor T3 is effectively grounded via resistors R8 and R6 (shunted by the load of the first gadget). As a result, transistor T3 is forward biased and gadget 2 gets the supply. This is indicated by glowing of LED2. Circuit diagram : Solid-State Switch For Dc-Operated Gadgets Circuit Diagram Whe

Amplifier Circuit 2 X 10 watt with IC AN7145

This is Stereo Amplifier On this schematic amplifier circuit use the ic AN7145L , but can use the following IC : AN7145M AN7145H AN7146M AN7146H You can use of all ic above. anthis circuit need suply voltage with dual voltage . Minimum voltage 6 Volt and maximum voltage 20 volt . Voltage just (-) and (+), but (-) can also ground. Maximum power output 2 X 20 watt with minimum impedance 4 ohm. Click image to view enlarge. You can operate this circuit with plugging input to , PC or other media can give signal audio.

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