A children's care home worker deliberated tampered with a CCTV system at a property in Preston to avoid being rumbled for engaging in sexual activity with a child, a court heard.
Mark Woodrow, 34, of Wellington Road, Ashton-on-Ribble, Preston, pleaded guilty to sexual activity with a child under 18.
Preston Crown Court heard the girl had been left feeling "confused" by the events.
Woodrow, who began employment in April with Lancashire firm Pathways as a carer, had been communicating with the youngster between June 2 and 4 by text and on Facebook.
On June 4 overnight into June 5 he had intercourse with her at an address in the city.
The court heard he had previously met the teenager when he had taken patients from his last job at Whittingham Hospital for a visit to her then workplace.
Mr Brown added: "She was troubled by what had gone on and mentioned it to her mother the following day."
The defendant was suspended from the home on June 8 after a police investigation began.
He was interviewed and made a full admission.
Mr Brown added: " There's a clear attempt to conceal evidence by the switching off of the camera."
The court heard Woodrow had been bullied as a child, and suffered Klinefelter syndrome, in which boys are born with an extra X chromosome.
Judge Andrew Woolman said texts Woodrow had sent were "going beyond the normal relationship that would have been proper, and going into a relationship of a personal nature" between them.
He added: " She was to be regarded as a child. You were 34, an adult with responsibilities.
"You were devious in one sense."
"I've come to the conclusion, with a degree of reluctance, that because of the determined nature of this offence it wouldn't be right for me to suspend your sentence. You were twice her age and you put you own sexual needs before the needs of a vulnerable girl."
He was given a two year restraining order and will be subject to notification requirements for 10 years.
It emerged in court that Woodrow had resigned from his former job at Whittingham Hospital after allegations - later unfounded - were made against him about being inappropriate with female staff.