+12V/-12V Power Supply unit: To work the circuit which used the operational amplifier and so on, the positive and the negative power
supply become necessary. The power supply which I introduce here is the one to have used the unit which has the two power supplies of 12 V in
the one unit.
The power supply unit is using the ready-made. It inputs AC100 V and it is possible to take out 12 V of the two DCs which are independent as
the output. (Electronic circuit added 4/05) |
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12V to 9V car converter:
(Electronic circuit added 4/05) |
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Algorithm Tests for Point Location: 08/03/00 EDN-Design Ideas
/ (Circuit / schematic design added 6/06) |
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Algorithm Transforms Filter Coefficients: 01/21/99
EDN-Design Ideas / (Circuit / schematic design added 6/06) To synthesize infinite-impulse-response (IIR)-filter functions, expressed as H(z),
you commonly use analog prototype-filter functions, expressed as H(s), using the bilinear-z transform. This operation entails some algebraic
complexity in calculating the filter coefficients. The simple algorithm shown here transforms the prototype-filter coefficients (W0, W1, W2)
to the IIR digital-filter coefficients (U0, U1, U2). These coefficients transform from the s (analog) domain to the z (digital) domain.... |
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An Acoustic Transformer Powered Super-High Isolation Amplifier: National
Semiconductor - Application Note (app note added added 6/06) |
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AN-285: An Acoustic Transformer Powered Super-High Isolation Amplifier: National
Semiconductor - Application Note (app note added 6/06) |
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Connect line-level signal to
phono input : The circuit does two functions: signal level attenuation and inverse RIAA filtering. The signal attenuation is needed
to convert the 500 mV signal to 2.5 mV signal. The inverse-RIAA filtering is needed to make the frequency response of the system flat (same
equalization that is used when music is transferred to vinyl in the studio). The picture blow shows the frequency response of the ideal
inverse-RIAA filter (Schematic / circuit added 10/05) |
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Everything you Wanted to know
About Wideband Low frequency Transformers: 11/23/00 EDN-Design Ideas / (added 5/03) |
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External
Isolation Transformer Box: designed for Mackie and other Mixers Eliminates RFI Problems (Electronic Schematic / circuit added 4/02) |
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Grounding
& Shielding: describes basic audio transformer uses like balanced in/out and signal splitters (Electronic Schematic / circuit added
4/02) |
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High CMRR
Balanced Interface: Uses for Crystal18 or20 Bit A/D Converters. This is a PDF file (Electronic Schematic / circuit added 4/02) |
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High
Output Line Driver for Single Ended Power Supply: PDF file (Electronic Schematic / circuit added 4/02) |
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IC Mic
Preamp uses Jensen Twin Servo topology: (added 8/02) |
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Interconnection of Balanced & Unbalanced Equipment: 4 page booklet in PDF format (Electronic Schematic / circuit added 4/02) |
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Internal
Modification to Mic Inputs of the Mackie 1604 Mixer Eliminates RFI Problems: adding transformer isolation increases common mode
rejection and eliminates RF interference, PDF document (Electronic Schematic / circuit added 4/02) |
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Isolation Transformer Passes Millihertz Signals: 08/04/94 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) You can
successfully use an ordinary low-cost line transformer as an isolation transformer in ac circuits that require floating sources. However, at
frequencies below 20 to 30 Hz, high distortion and excessive phase shifting occur. The simple circuit in Fig 1 restores the phase and
frequency response down into the millihertz region. Based on phase-response data, the low-end frequency response extends below 100 mHz...
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Isolator
transformer for audio lines: If you want to do the ground loop elimination in audio path, you have to cut the galvanic connection
but pass the whole audio range. The simplest and most common way to do the isolation is use audio transformer which is ment for audio use.
Transformers for audio use have some problems like distorted bass response and attenuating in high-frequency response. Basically a transformer
slows down upper frequencies and allow the low frequencies to pass first, creating what we perceive as a "fat/warm" tone. Inadequate frequency
response on the low end (rolloff at like 20Hz), causes low frequencies to be "slowed", allowing the upper frequencies to be heard first, this
is perceived as "barky/ brittle". High-quality audio transformers cover whole audio band with good response, but those are quite
expensive....(Schematic / circuit added 10/05) |