What's inside the box: SSD Circuit
We only design, build and sell devices that come with meters. The device you use for tDCS should be able to tell you how many mAmps you are using in your session - that is what the meter is for - If your device does not have a meter then you can not know for sure what parameters your tDCS session has and it will be hard to learn what works best for you.
FIXED VOLTAGE and SELECTABLE VOLTAGE.
We design, build and sell only FIXED VOLTAGE DEVICES.
Some tDCS manufacturers use a VARIABLE VOLTAGE CIRCUIT which (in theory) compensates for changes in electrode resistance during a tDCS session but we think this adds an unnecassary risk and is not a good design choice.
Rather than having a variable voltage circuit we offer devices that allow you to select a higher fixed voltage if you are having trouble achieving your target mA level. If you are doing complicated montages (i.e. montages involving placement of the electrodes over hair) or are one of those people whose skin has a naturally high level of resistance, our selectable voltage devices allow you to select a higher voltage.
Our newest model comes as a 12V or as a Selectable 12-24V.
Both models have all the features required for safety, comfort, and efficacy.
SAFETY Features. TESTING and Calibration.
Each SSD tDCS device comes with these safety features/components:
LM334z. This is a Current Regulator that sets the maximum current output (e.g. a higher voltage will not produce higher current but will overcome higher resistance electrode placements such as hair, skin, etc much more easily). No SSD device will exceed 2.30 mA at any voltage.
All our devices have two LM334z for added safety.
Reverse Polarity Protection Diode is used so the circuit will not function if the battery is accidentally put in the wrong way.
Analog mA Current Meter. We use a meter with a 3mA scale because it is a perfect fit for tDCS applications.
The meter is tested before assembly and then calibrated for accuracy.