Small PDF document for the STK412-150, a Sanyo hybrid power amplifier module used in many home audio systems and mini hi-fi units.

2.1 amplifier schematic using the 2SC5200 and 2SA1943 complementary power transistor pair, in a 184 KB PDF.

Another reference for the IRF540 power MOSFET, provided as a 117 KB PDF and indexed as a schematic despite being named a datasheet.

Cellular network section schematic for the Samsung SM-A22 5G, a 5.26 MB PDF. It covers the RF chain, including transceiver, power amplifiers, antenna switches and the…

Audio Pro Ace Bass A101 service manual, with the int tag suggesting an integrated amplifier, though the name does not state this firmly.

BIOS package for the Lenovo Zhaoyang K42, model code 80CIZV0, built on Compal board LA-E581P, revision 2A, dated 2017-03-22, with an 8 MB image size noted.

The 2SD2129 transistor is documented in this 216 KB PDF datasheet, catalogued among schematics.

The 2SC5421 transistor is the subject of this 323 KB PDF, likely a datasheet since 2SC stands for a JIS-registered NPN bipolar device.

Datasheet PDF, 64.6 KB, for the KA7500B, a PWM control IC from the KA7500 series and a TL494-style design widely found in computer power supplies.

Only the part number 2SJ275 appears in the name of this 97.0 KB PDF. That code follows Japanese JIS numbering, where 2SJ indicates a P-channel field-effect transistor…

Named after the JIS part number 2SJ267, this 91.8 KB PDF most likely documents a P-channel field-effect transistor, since the 2SJ prefix denotes that device class.

Audio Pro Ace Bass B2-40 subwoofer service manual in PDF form, about 1.96 MB, as indicated by the sub and sm tags.

Datasheet-type PDF for the 3SK271, around 32.7 KB, catalogued in the schematic category.

PDF schematic titled simply 4kw, most likely a high-power audio amplifier rated around 4 kilowatts.

Version 1.0 service schematic for the Sony MEX-BT5100 car stereo with Bluetooth, delivered as a 6.42 MB PDF.

Firmware archive for LCFC board NM-F091 revision 1.0, listed for the KY580, KY581, KY582, KY583, KY780, KY783 and KY784 project codes.

Compact 25.2 KB PDF named for the 3SK301, categorised as a schematic but most likely a part datasheet. Nothing besides the type number appears in the name.

Component PDF for the 3SK285, 22.2 KB, placed in the schematic section of the index. Only the part number is given.

A 111 KB PDF for the 2SK1453, placed among schematics, although the part-number naming points to a component data sheet.

Compact 42.7 KB PDF covering the 2SB1183 transistor. The JIS-style 2SB prefix identifies a PNP device designed mainly for low-frequency circuits, commonly found in power…

Datasheet material for the 2SB1037 transistor, delivered as a 122 KB PDF in the schematic category.

Component placement drawing for the Apex AX 20 amplifier board, a 61 KB PDF. It shows where each resistor, capacitor, transistor and connector sits on the PCB, which…

An 88.0 KB PDF for the 2SD1838, a Japanese-registered NPN bipolar transistor, best treated as a datasheet even though it is indexed as a schematic.

PDF datasheet for the 2SD879 transistor, roughly 106 KB, with no manufacturer indicated in the file name.

Datasheet PDF, about 180 KB, for the 2SB1481, filed in the schematic section of the index under its bare JIS part number.

Datasheet for the SG2524, a 107 KB PDF covering a member of the long-established 2524/3524 family of regulating pulse-width modulators.

Mirrored PCB artwork for a Zener amplifier board, a 237 KB PDF; espejo is Spanish for mirror.

Audio Pro A101 service documentation in PDF form, about 3 MB, with the int-sm tag pointing to an international service manual version.

Sony schematic for the MEX-BT5000 car stereo with Bluetooth, provided as a 6.75 MB PDF with no version indicated.

The 3SK263 is covered by an 82.7 KB PDF placed in the schematic category, though a part-number name like this normally indicates a component datasheet.

The file name gives nothing beyond 2SC3460, a Japanese JIS designation in which the 2SC prefix denotes an NPN bipolar transistor.

Compact 41.4 KB PDF for the 2SB987, with an _E suffix not explained by the name, perhaps an edition or language marker.

Copper-side PCB artwork for the Apex AX 20 amplifier project, a 208 KB PDF showing the track pattern rather than a circuit diagram.

Class H power supply schematic, version 0.2, fuse type, marked final, in a 1.39 MB PDF.

PDF datasheet for the MPSA64, a PNP Darlington transistor that the name lists at -30 V and 800 mA.

Datasheet-style document for the 3SK302, a 26.0 KB PDF indexed as a schematic. The 3SK prefix in Japanese JIS numbering denotes a four-terminal N-channel field-effect…

PDF for the 2SD1992A NPN transistor, indexed as a schematic though the name points to a part datasheet.

The 466 KB PDF here is titled only 2SC4841, a Japanese JIS transistor code where 2SC stands for NPN.

Yamaha PA 2400 amplifier schematic in a small 194 KB PDF. The name gives no revision or note about modifications, so it may represent the standard circuit, but confirm…

Schematic in PDF form for a stereo preamplifier with a loudness control, a common DIY audio circuit that boosts bass and treble at low listening volume.