# Sixth Lichuang Electric Competition #OCL AMP

* 1. Introduction to project functions

Build OCL two-channel power amplifier with discrete components.

*2. Project attributes

Please enter content...

* 3. Open source agreement

GPL 3.0

Please fill in during the competition stage↓

*4. Hardware part

   This OCL high-power amplifier is a typical OCL circuit. The circuit adopts direct coupling method and has good low-frequency response. The input stage adopts differential amplification and has very little noise. The output stage adopts Darlington composite tube, which has high gain, high power and distortion. Small; this circuit is especially suitable for making power amplifier circuits for home power amplifiers and active speakers, and the effect is very good.
    The OCL high-power amplifier kit is a two-channel, and the two-channel circuit principle is exactly the same. Taking the left (L) channel as an example, Q4 and Q5 in the circuit are the differential amplification input stages, Q2 is the excitation stage, Q3 and Q6, Q7 and Q8 forms a composite complementary output stage. The output signal is taken out from the Q6 emitter and Q8 collector. The output audio signal can directly drive the speaker to emit loud sound. This circuit also adds R13, R25, C8, and C22 to reduce static noise.
    The transformer (T) used in the OCL high-power amplifier kit is a center-tapped dual power transformer with a primary voltage of AC220V, a secondary set of two sets of AC12-15V, and a power of 10-100W (can be determined according to needs).

    Power supply voltage: dual power supply AC12-18V
    Output power: Po=20W+20W (RL=8Ω), 30W+30W (RL=4Ω)
    Load impedance: 4-8 ohms (8 ohms/30-60W is recommended for speakers)

   See the circuit diagram for details. There is a small bug, the flash light does not light up. After checking, it seems that I bought a fake LM3915N on Taobao. I will buy another one to try again and upload the video of the flash light.

*5. Software part

Please enter content...

Pure hardware, no software.

*6. BOM list

Please enter content...

Note: BOM list involved in the project. Please upload a screenshot of the BOM at this location. Please upload the list details in PDF format to the attachment. Suggestions include model, brand, name, packaging, procurement channels, usage, etc. The specific content and form should be based on clearly expressing the project composition.

*7. Contest LOGO verification

Please upload a project picture containing the competition logo. The logo will be printed on the PCB in the form of silk screen printing.

Click the zip to download the competition logo! (Contest logo).zip

* 8. Demonstrate your project and record it as a video for uploading

Video requirements: Please shoot horizontally, with a resolution of no less than 1280×720, in Mp4/Mov format, and the size of a single video is limited to 100M;

Video title: Lichuang Electric Competition: {Project Name}-{Video Module Name}; such as Lichuang Electric Competition: "Autonomous Driving" - Team Introduction.

More details: https://diy.szlcsc.com/posts/06c94d90c2c447dfbd9ed7339ff4a5b1