Owing to the recent launching in Europe of Cranial Electrotherapy Stimulation (CES) portable sets, we have been "Electronically Stimulated" in designing a similar circuit for the sake of Hobbyists. CES is the most popular technique for electrically boosting brain power, and has long been prescribed by doctors, mainly in the USA, for therapeutic reasons, including the treatment of anxiety, depression, insomnia, and chemical dependency. CES units generate an adjustable current (80 to 600 microAmperes) that flows through clips placed on the earlobes. The waveform of this device is a 400 milliseconds positive pulse followed by a negative one of the same duration, then a pause of 1.2 seconds. The main frequency is 0.5 Hz, i.e. a double pulse every 2 seconds. Some people report that this kind of minute specialized electrical impulses contributes to achieve a relaxed state that leaves the mind alert. R1_____________1M5  1/4W ResistorR2_____________15K  1/4W ResistorR3____________100K  Linear PotentiometerR4_____________2K2  1/4W ResistorC1___________330nF  63V Polyester CapacitorC2___________100µF  25V Electrolytic CapacitorD1_____________3mm  Red LEDIC1___________7555  or TS555CN CMos Timer ICIC2___________4017  Decade counter with 10 decoded outputs ICSW1___________SPST  Slider SwitchB1______________9V  PP3 BatteryClip for PP3 Battery Two Earclips with wires (see notes)Circuit operation:IC1 forms a narrow pulse, 2.5Hz oscillator feeding IC2. This chip generates the various timings for the output pulses. Output is taken at pins 2 & 3 to easily obtain negative going pulses also. Current output is limited to 600µA by R2 and can be regulated from 80 to 600µA by means of R3. The LED flashes every 2 seconds signaling proper operation and can also be used for setting purposes. It can be omitted together with R4, greatly increasing battery life.Notes:    * In order to obtain a more precise frequency setting take R1=1M2 and add a 500K trimmer in series with it.    * In this case use a frequency meter to read 2.5Hz at pin 3 of IC1, or an oscilloscope to read 400msec pulses at pins 2, 3 or 10, adjusting the added trimmer.    * A simpler setting can be made adjusting the trimmer to count exactly a LED flash every 2 seconds.    * Earclips can be made with little plastic clips and cementing the end of the wire in a position suited to make good contact with earlobes.    * Ultra-simple earclips can be made using a thin copper foil with rounded corners 4 cm. long and 1.5 cm. wide, soldering the wire end in the center, and then folding the foil in two parts holding the earlobes.    * To ensure a better current's transfer, this kind of devices usually has felt pads moistened with a conducting solution interposed between clips and skin.    * Commercial sets have frequently a built-in timer. Timing sessions last generally from 20 minutes to 1 hour.