Un tipo de fuente de alimentación muy simple y útil es aquella que no usa el transformador. Si bien este componente es muy recomendable, dado el aislamiento que proporciona, hay casos en los que, por economía, limitaciones de espacio o incluso la falta de tanta seguridad, se puede utilizar una fuente de alimentación sin transformador. Estas fuentes aprovechan la reactancia capacitiva de un capacitor, generalmente de poliéster de alta tensión, para reducir la tensión de la red eléctrica. Posteriormente se realiza la rectificación, filtrado y regulación. Las fuentes típicas sin transformador se utilizan para alimentar dispositivos de bajo consumo como calculadoras, relojes y otros equipos similares cuya tensión suele estar en el rango de 1,5 a 9 V. Las corrientes requeridas por estos dispositivos no deben exceder los 20 mA. Con corrientes más altas, los capacitores requeridos serían muy grandes, en cuyo caso el transformador comienza a ser más interesante. En la figura tenemos el circuito de una fuente sin transformador para corrientes de hasta 20 mA. El diodo Zener determina la tensión de salida. El capacitor de poliéster tiene diferentes valores, dependiendo de si la red es de 110 V o 220 V. Los valores entre paréntesis son para la tensión de 220 V. Su tensión de trabajo debe ser al menos el doble de la tensión de la red a la que va el circuito. para ser utilizado. Es importante tener mucho cuidado con el aislamiento de todas las partes del dispositivo que deben estar alimentadas y de la propia fuente, ya que está conectada directamente a la red. Ningún equipo con partes metálicas o eléctricas expuestas debe alimentarse con este tipo de fuente.

 

Fuente sin transformador
Fuente sin transformador

 

 

 

18.837MBMemory Usage41.39msRequest Duration
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