# 7812 Audio Amplifier PCB ## Description Transformer-isolated rectifier, 7812 regulated 12 V supply, and 2N2222 single-transistor audio amplifier PCB recreated from the reference circuit image. ## Project Details - **Owner:** s-sabry - **Created:** 5/19/2026 - **Last Updated:** 5/19/2026 - **Visibility:** Public ## Key Components ### BR1 — [CD-MMBL110S](https://www.flux.ai/jecstronic/cd-mmbl110s~4ej.md) - Role: Rectification - Datasheet URL: https://www.mouser.ca/datasheet/2/54/Bourns_CD_MMBL110S_datasheet-2586146.pdf - Part Type: Bridge Rectifiers - Manufacturer Part Number: CD-MMBL110S - Manufacturer Name: Bourns - Role Details: Full-wave rectifies the isolated transformer secondary before bulk filtering. - Forward Voltage: 900mV **Pins:** - - - + - ~_1 - ~_2 ### J1 — [WJ2EDGRC-5.08-02P-14-00A](https://www.flux.ai/adrian95/wj2edgrc-5p08-02p-14-00a~gk9.md) - Role: Isolation - LCSC Part Number: C3697 - Part Type: Connector - Manufacturer Part Number: WJ2EDGRC-5.08-02P-14-00A - Role Details: Accepts isolated AC from the off-board transformer secondary; mains primary is not placed on this low-voltage PCB. - Datasheet URL: https://www.lcsc.com/datasheet/C3697.pdf?spm=wm.sxq.inf.ggs&utm_source=octopart&lcsc_vid=T1kIXgFeT1NaU1RXQFBbUlUHT1cKU1NXFVBeX1VSTlAxVlNRT1lXUFFXQ1FaUzsOAxUeFF5JWA4NEwsWFhMaSQcJGk4%3D - Manufacturer Name: KANGNEX - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - P1 [pin 2] - P2 [pin 1] ### J2 — [WJ2EDGRC-5.08-02P-14-00A](https://www.flux.ai/adrian95/wj2edgrc-5p08-02p-14-00a~gk9.md) - Part Type: Connector - Manufacturer Part Number: WJ2EDGRC-5.08-02P-14-00A - Role: Coupling - Role Details: External low-level audio signal input connector replacing the simulator sine source. - LCSC Part Number: C3697 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: KANGNEX - Datasheet URL: https://www.lcsc.com/datasheet/C3697.pdf?spm=wm.sxq.inf.ggs&utm_source=octopart&lcsc_vid=T1kIXgFeT1NaU1RXQFBbUlUHT1cKU1NXFVBeX1VSTlAxVlNRT1lXUFFXQ1FaUzsOAxUeFF5JWA4NEwsWFhMaSQcJGk4%3D **Pins:** - P1 [pin 2] - P2 [pin 1] ### Q1 — [2N2222AUB](https://www.flux.ai/jecstronic/2n2222aub~0jf.md) - Datasheet URL: https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Datasheet/2N2222AUB.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TT Electronics/Optek Technology - Role: Amplification - Part Type: Transistor - Manufacturer Part Number: 2N2222AUB - Role Details: Single-transistor common-emitter audio output driver stage. **Pins:** - B [pin 1] - C [pin 2] - E [pin 3] ### RV1 — [3386P-1-103LF](https://www.flux.ai/adrian95/3386p-1-103lf~2jg.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Voltage Division - Manufacturer Part Number: 3386P-1-103LF - Part Type: Potentiometer - Manufacturer Name: Bourns Inc. - Datasheet URL: https://www.bourns.com/docs/Product-Datasheets/3386.pdf - Role Details: Trimmer connected across regulator input and ground as shown in the reference schematic. **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### RV2 — [3386P-1-103LF](https://www.flux.ai/adrian95/3386p-1-103lf~2jg.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Biasing - Manufacturer Part Number: 3386P-1-103LF - Part Type: Potentiometer - Datasheet URL: https://www.bourns.com/docs/Product-Datasheets/3386.pdf - Role Details: Adjustable bias/level control feeding the 2N2222 base node. - Manufacturer Name: Bourns Inc. **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### U1 — [LM7812CT/NOPB](https://www.flux.ai/adrian95/lm7812ctnopb~3wf.md) - Role: Power Conversion - Package or Case Code: TO254P470X1028X1955-3P - Role Details: Regulates rectified transformer secondary to 12 V rail for the amplifier; sized for speaker/amplifier load. - Manufacturer Name: Texas Instruments - Datasheet URL: http://www.ti.com/lit/ds/symlink/lm340.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: LM7812CT/NOPB - Part Type: Power Management **Pins:** - GND [pin 2] - INPUT [pin 1] - OUTPUT [pin 3] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/s-sabry/7812-audio-amplifier-pcb~vz](https://www.flux.ai/s-sabry/7812-audio-amplifier-pcb~vz).* --- *Generated from [https://www.flux.ai/s-sabry/7812-audio-amplifier-pcb~vz](https://www.flux.ai/s-sabry/7812-audio-amplifier-pcb~vz)*