Schematic Volt

Audio Stereo Channel Selector Circuit

This circuit has accouterment for abutting stereo outputs from four altered sources/channels as inputs and alone one of them is selected/connected to the achievement at any one time.

When ability accumulation is angry ‘on’, approach A (AR and AL) is selected. If no audio is present in approach A, the ambit waits for some time and again selects the abutting approach (channel B). This chase operation continues until it detects audio arresting in one of the channels. The inter-channel adjournment or adjournment time can be adapted with the advice of preset VR1. If still best time is needed, one may alter capacitor C1 with a capacitor of college value.

Suppose approach A is affiliated to a band recorder and approach B is affiliated to a radio receiver. If initially approach A is selected, the audio from the band recorder will be present at the output. After the band is played completely, or if there is acceptable abeyance amid after recordings, the ambit automatically switches over to the achievement from the radio receiver. To manually skip over from one (selected) alive approach to addition (non-selected) alive channel, artlessly advance the skip about-face (S1) briefly already or more, until the adapted approach ascribe gets selected. The called approach (A, B, C, or D) is adumbrated by the aglow of agnate LED (LED11, LED12, LED13, or LED14 respectively).

IC CD4066 contains four alternation switches. These switches are affiliated to four abstracted channels. For stereo operation, two agnate CD4066 ICs are acclimated as apparent in the circuit. These alternation switches are controlled by IC CD4017 outputs. CD4017 is a 10-bit arena adverse IC. Since alone one of its outputs is aerial at any instant, alone one about-face will be bankrupt at a time. IC CD4017 is configured as a 4-bit arena adverse by abutting the fifth achievement Q4 (pin 10) to the displace pin. Capacitor C5 in affiliation with resistor R6 forms a power-on-reset ambit for IC2, so that on antecedent switching ‘on’ of the ability supply, achievement Q0 (pin 3) is consistently ‘high’. The alarm arresting to CD4017 is provided by IC1 (NE555) which acts as an astable multivibrator back transistor T1 is in cut- off state.

IC5 (KA2281) is acclimated actuality for not alone advertence the audio levels of the called stereo channel, but additionally for advanced biasing transistor T1. As anon as a specific beginning audio akin is detected in a called channel, pin 7 and/or pin 10 of IC5 goes ‘low’. This low akin is accompanying to the abject of transistor T1, through diode-resistor aggregate of D2-R1/D3-R22. As a result, transistor T1 conducts and causes achievement of IC1 to abide ‘low’ (disabled) as continued as the called approach achievement exceeds the preset audio beginning level.

Presets VR2 and VR3 accept been included for acclimation of alone audio beginning levels of larboard and appropriate stereo channels, as desired. Already the multivibrator activity of IC1 is disabled, achievement of IC2 does not change further. Hence, analytic through the channels continues until it receives an audio arresting beyond the preset beginning value. The skip about-face S1 is acclimated to skip a approach alike if audio is present in the called channel. The cardinal of channels can be calmly continued up to ten, by application added 4066 ICs.

Car Audio Amplifier Circuit:

Given below is a car stereo amplifier circuit using audio amplifier IC – TDA2040

Description of the circuit:

A car stereo amplifier circuit using TDA2040 is shown here. TDA2040 is a monolithic integrated audio amplifier that operates in Class AB mode. The IC has built in circuitry for short circuit protection and thermal shut down and more over it can be operated from a single supply too. The amplifier can deliver 12 watts into to a 8 ohm speaker.

In the circuit the IC is wired in order to operate from the cars 12V line. Capacitor C7 is the input DC decoupling capacitor and R4 provides feedback. Network consisting of resistor R5 and capacitor C5 provides high frequency stability and prevents any chance of oscillation. Capacitor C6 couples the ICs output to the speaker. C2 and C1 are power supply filters.

Circuit diagram of car stereo circuit using TDA2040

Notes.

• Quality of the PCB is a very crucial factor in the amplifiers performance.
• The amplifier can be operated from cars 12V line.
• Heat sink is necessary for TDA2040.
• All electrolytic capacitors must be rated 15V.
• Only one channel is shown here. For stereo application you must make one more identical copy. 

Download the datasheet document of KA2211 HERE

On the amplifier circuit using ic STK, the same as my previous posting. However, in the above circuit has 2 inputs and 2 outputs, or commonly called a stereo amplifier. This issue of power amplifier 2 x 18Watt and has impedance 8. To stress that it takes about 35-38Volt.