Controlling LED light and electrical shock via a transistor-relay circuit


In the two-way active avoidance experiment, LEDs were used as a conditioned stimulus (CS), and the electrical shock was used as an unconditioned stimulus (US). I made a set up in which LED and electrical shock can be controlled in LabVIEW. I used a transistor circuit that works as a switch that control the relays which turn on and of the LED and voltage.

Left page, right page in pdf.

DAQ (data acquisition device) can provide only a small current (~mA) which cannot directly drive the LEDs and other devices that require a larger current. LEDs can be turned on or off by the relay. The mechanical action of the relay can be controlled by the transistor that works as swith. The transistor can be controlled by the small amount of currents provided by the DAQ.


  1. Identification of a neuronal population in the telencephalon essential for fear conditioning in zebrafish. Pradeep Lal, Hideyuki Tanabe, Maximiliano L. Suster, Deepak Ailani, Yuri Kotani, Akira Muto, Mari Itoh, Miki Iwasaki, Hironori Wada, Emre Yaksi and Koichi Kawakami. BMC Biology 2018 16:45 Open Access
  2. 第2章  トランジスタをスイッチとして使う(PDF)