How to build electrodes and grids:

1. Design of electrodes to measure weak electric field components:

Main features are high input impedance and low input noise. We use industrial standard 2SK596S JFET, 20 V, 150 to 350 µA, 1.0 mS, N-Channel

You can buy the JFET or an EMY-62L3 microphone capsule by EKULIT (conrad electronics) which is based on the same JFET.

Remove the black cover, aluminium capsule and acoustic membrane carefully see photos on the right

2. Circuit diagram for single electrodes:

Sensor and cable driver wiring: see diagram on the right.

Microphone capsule EMY 3: 

Built-in JFET 2SK596S:   

Impedance converter: necessary for long cables up to 10 m and for audio boxes with low input resistance < 100 kOhm

Op-amp LF 351 or similar

Trim pot 50 kOhm at 12 V DC (use 10 kOhm if running with 5 V)

Note: the voltage from the insect can easily exceed 100 V !
      Keep a distance of > 3 cm

 We recommend a 24 bit audio box.

3. Examples of grids with 32 electrodes:

      Left: 32 x EMY 3, spacing 1.5 cm

      Right: 32 x 2SK596S JFET, spacing 5.5 mm