Detonator ignition protection and detection circuit

A method for testing an ignition circuit of a detonator having two test lead wires, the ignition circuit having a predefined capacitance and a predefined resistance range as measured at an upstream end of the two test lead wires connected to the detonator, the method comprising:

• using an electrical circuit tester:
• measuring a DC resistance of the ignition circuit from a reference point upstream of and across the two test lead wires;
• comparing the measured resistance with the predefined resistance range, and adjusting a circuit gain where the measured resistance is within the predefined resistance range, but on a low side of the range;
• injecting an AC reference voltage into the two test lead wires, and calculating a resultant phase angle between the AC reference voltage and a resultant AC current;
• determining if the calculated phase angle is within a predefined range based on the predefined capacitance;
• providing a signal in response to at least one of:
• the measured resistance being outside of the predefined resistance range;
• the calculated phase angle being outside of the predefined range;
• the measured resistance being inside the predefined resistance range;
• and, the calculated phase angle being inside the predefined range.

An electrical circuit tester comprising:

• a housing having input/output ports disposed and configured for electrical communication external of the housing;
• a microprocessor-based controller disposed within the housing;
• a user interface disposed and configured in electrical communication with the controller;
• and
• DC and AC circuitry disposed and configured in electrical communication with the controller;
• wherein the DC circuitry is configured to provide a DC voltage at the input/output ports, and to receive a DC current signal in response to the input/output ports being electrically connected to an electrical impedance, wherein the controller is responsive to executable instructions to calculate a DC resistance based on the DC voltage and the DC current signal;
• wherein the AC circuitry is configured to provide an AC reference voltage waveform at the input/output ports, and to receive an AC current waveform in response to the input/output ports being electrically connected to the electrical impedance, wherein the controller is responsive to executable instructions to calculate an electrical phase angle between the AC reference voltage waveform and the AC current waveform;
• wherein the microprocessor-based controller is further responsive to executable instructions which when executed by the microprocessor-based controller is capable of performing a method, the method comprising:
• measuring a DC resistance of the ignition circuit from a reference point upstream of and across the two test lead wires;
• comparing the measured resistance with the predefined resistance range, and adjusting a circuit gain where the measured resistance is within the predefined resistance range, but on a low side of the range;
• injecting an AC reference voltage into the two test lead wires, and calculating a resultant phase angle between the AC reference voltage and a resultant AC current;
• determining if the calculated phase angle is within a predefined range based on the predefined capacitance;
• providing a signal in response to at least one of:
• the measured resistance being outside of the predefined resistance range;
• the calculated phase angle being outside of the predefined range;
• the measured resistance being inside the predefined resistance range;
• and, the calculated phase angle being inside the predefined range.