Product description
Electrokit EK038 is a 1 W audio amplifier soldering kit. The kit contains everything needed to build a small amplifier and is based on the LM4861 amplifier IC. The amplifier is a mono type (single channel) and can deliver up to 1.5 W into 8 Ω. The amplifier IC operates from 2.5–5.5 VDC, providing considerable flexibility. The differential outputs eliminate the need for a large output capacitor, saving space. The LM4861 features built-in thermal protection that shuts down the amplifier in the event of overheating.
Thanks to its versatile connection options – direct wiring, 3.5 mm jack (AUX), screw terminals or pin headers – the amplifier is suitable for a wide range of audio projects. The AUX input allows the amplifier to be easily connected to devices such as mobile phones, media players and computers with a headphone output.
The pin header can be mounted on the underside of the PCB, making the amplifier compatible with breadboards and prototyping boards. Alternatively, it can be mounted on the top side for connection to an Arduino Uno or a microcontroller with a DAC using female-to-male dupont jumper wires.
The LM4861 uses a bridge-tied load (BTL) output configuration, meaning that the speaker is connected between two active amplifier outputs rather than between an output and ground. The outputs operate in opposite phases, providing twice the voltage swing across the speaker compared with a conventional single-ended amplifier. This makes it possible to achieve higher output power even at a relatively low supply voltage.
Another advantage of the bridge configuration is that the speaker does not require a series-connected output capacitor. Both outputs have the same DC voltage level, meaning that no DC voltage is applied across the speaker. This design therefore requires fewer components and avoids the limitation in bass response that an output capacitor might otherwise introduce.
The PCB has four mounting holes (M2.5) for installation in equipment and enclosures. The board also has pre-drilled holes for mounting a horizontal 16 mm potentiometer (see one of the product images), which is sold separately. A vertical potentiometer is included in the kit.
Specifications:
- Amplifier IC: LM4861
- Type: Mono amplifier, Class AB
- Supply voltage: 2.5–5.5 VDC
- Output power: 1 W at 5 V, 8 Ω and 1% THD+N (typical)
- Output power: 1.5 W at 5 V, 8 Ω and 10% THD+N (typical)
- Recommended speaker impedance: 8 Ω
- Distortion (THD+N): Typically 0.72% at 1 W, 8 Ω
- Audio input: Line level (AUX)
- Quiescent current: Typically 6.5 mA at 5 V
- Frequency range: 20 Hz–20 kHz
- Protection: Thermal shutdown protection
- IC operating temperature: −40 to +85 °C
- Soldering skill level: Beginner to intermediate
- Dimensions: 40 x 38 mm
Included:
- All necessary components (see the parts list in the documentation)
- Pin header
- Screw terminal blocks
- Vertical potentiometer (volume control)
- 3.5 mm female audio jack (AUX)
