A method of making a respirator, which method includes placing an electret in a respirator body that is adapted to fit over the nose and mouth of a wearer. A monitoring and control circuit section that is an integrated circuit element built in the electronic control unit includes a self-test circuit configured with a built-in self-test control block, scan chain circuits and mask circuitry, and performs a self-test using the built-in self-test control block and a partial combination of the scan chain circuits at start of the operation. The electrostatic discharge protection circuit couples the channel to the passive filter.