El amplificador de bancada que describimos en este artículo cuenta con un paso amplificadores de ganancia elevada, para permitir su uso en la prueba de micrófonos de baja impedancia y otras fuentes de señal muy débil. Alimentado por las pilas es totalmente portátil.

Describimos el montaje de un sensible amplificador de prueba para la bancada que funciona también como un seguidor de señales de audio muy sensible.

El circuito es alimentado por pilas y tiene una etapa preamplificadora de alta ganancia con dos transistores.

Usamos el TDA7052, pero nada impide que otros amplificadores de audio como el LM386 sean utilizados, siempre y cuando la placa de circuito impreso sea alterada.

 

Montaje

En la figura 1 tenemos el diagrama completo del amplificador de prueba.

 

Figura 1 - Diagrama completo del amplificador
Figura 1 - Diagrama completo del amplificador | Haga click en la imagen para ampliar |

 

En la figura 2 tenemos una sugerencia de placa de circuito impreso para el montaje.

 

Figura 2 - Placa de circuito impreso para el montaje
Figura 2 - Placa de circuito impreso para el montaje | Haga click en la imagen para ampliar |

 

En el montaje, observe bien la posición del circuito integrado y de los transistores.

El altavoz puede ser del tipo pequeño de 5 a 10 cm, preferiblemente instalado en una caja, junto con el circuito.

Para mayor autonomía el circuito puede ser alimentado por pilas medias, pero nada impide que una pequeña fuente de 6 V sea utilizada.

 

Prueba y uso

Para probar el aparato basta con conectar una fuente de señal a la entrada o incluso colocar el dedo en el hilo vivo y abrir el control de volumen.

Debe haber la reproducción de la señal.

Para usar será interesante tener un enchufe con dos hilos dotados de garra y punta de prueba para realizar las pruebas en los equipos.

 

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