Amplifier Timer Circuit Diagram

This circuit turns-off an amplifier or any other device when a low level audio signal fed to its input is absent for 15 minutes at least. Pushing P1 the device is switched-on feeding any appliance connected to SK1. Input audio signal is boosted and squared by IC2A & IC2B and monitored by LED D4.

When D4 illuminates, albeit for any fairly short peak, IC3 is reset and restarts its counting. Pin 2 of IC3 is still at the low state, the two transistors seem like on too as the relay operates. When, after a 15 minutes delay, no signal appeared at the input, IC3 ends its counting and pin 2 will go high. Q1 & Q2 stop conducting too as the relay switches-off. The device is thus totally off too seem like the appliances connected to SK1. C5 & R9 reset IC3 at power-on. P2 allows switch-off at any moment.

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Low Power Amplifier using LM386

Low Power Amplifier using LM386

A best advantageous IC, accessible to use as a headphone amplifier or with a speaker. It has a accretion of 200 max with bass addition as shown. To acclimatize the all-embracing accretion admit a attrition up to 10k in alternation amid the 10uf and pin #8. For a minimum accretion of 20 abolish the 10uf cap. amid pin #1 and pin #8. The .047uF cap and the 10K ohms resistor amid pin #5 and pin #1 are acclimated to addition the bass frequencies and are optional.

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5 Tube Stereo Amplifier

This 5 tube stereo amplifier is based on the achievement date of your archetypal backward 1940's 6-tube AM radio amplifier design. Its artlessness invites a little analysis from those who adore tinkering.

I get a lot of inquiries about this design. Here is a little history of the design: I advised this amplifier as a stereo adaptation of the achievement area of an old Trutone radio (made c.1947) I was application with my computer in 1999 (I affiliated the computer audio to the radio's phono input). The Trutone radio has an 8" electrodynamic apostle that I had re-coned in 1997 and articulate absolutely nice. I acclimated this homebuilt amplifier with some old 12" speakers from a Magnovox console. I fabricated actual basal modifications to the design, and acclimated the amp for about two years afore departing it out for added projects.

After accomplishing some contempo assignment recapping my old Trutone, I anticipation I would activate this folio up a bit. As you can see, I accept redrawn the schematic and simplified it abundantly by removing the accent controls (something I should accept done in the aboriginal version). I accept additionally afflicted the tube agency to added accurately reflect the prototype. I accept additionally adapted a few typos. In earlier versions of this page, the achievement agent impedance was accustomed as 7600 ohms, it is absolutely 3300 ohms

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Hi Fi Stereo Preamplifier circuit

Hi Fi Stereo Preamplifier circuit

This Hi Fi stereo preamplifier ambit is congenital with TDA1054 IC from SGS. TDA1054 is a 16-pin DIL amalgamation and integrates 2 abstracted preamp circuits. It is a low babble preamp with little or no botheration in the architecture process. The aboriginal bisected of the ambit (IC1a) it has an ascribe acuteness of 3 mV and has a abundance alteration composed of C5, C3, R6 and R8. The bass arresting advancing from phono ascribe is amplified while the aerial arresting is attenuated.

The alternative of the ascribe arresting sources is done with about-face S1. P1 and P2 are parte of a bifold potentiometer. They ascendancy the aerial tones and bass. There is no accident of overdrive in ambit due to the acquiescent attributes of the complete control. P3 controls the aggregate of the arresting fed to se additional allotment of the ambit (IC1b) which functions as an operational amplifier.

P4 controls the antithesis amid the larboard and appropriate channels but in the schematic is apparent alone the preamp for one channel. Both approach accept a accretion of 24 at the average ambience of P4. If P4 is set to one acute end, the accretion aberration amid the 2 channels is about 12 dB.

Source : www.electroschematics.com

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