Regarding the field survey used in electrical measurement, it is generally divided into the following categories to give you a detailed description
I. Overview:      
The test pin is a probe for testing PCBA, which is mainly used as the input of electrical signals.
The surface is gold-plated, and the inside has a high-performance spring with an average life of 30,000 to 100,000 times.
Probe material: W, ReW, A +
1. At present, the main materials are W, ReW, general elasticity, easy to shift, sticky gold chips, need multiple cleaning, wear and tear, long needle life, and average life.
2. A + material free needle, this material has good elasticity, it is not easy to shift during the test, and it does not stick to gold chips, and is free of cleaning, so it has a long life.

Probe classification
Probes can be divided into:
A. Optical circuit board test probes: circuit board test before components are installed and only open-circuit and short-circuit detection probes;
B. On-line test probes: detection probes after mounting components on PCB circuit boards;
C. Microelectronic test probe: wafer test or chip IC test probe;
Third, the main types of probes: cantilever probes and vertical probes.
Cantilever Probes: Blade Type and Epoxy Type
Vertical Probe: Vertical Type
1.ICT probes (ICT series Probes)
Generally the diameter is between 2.54mm and 1.27mm. There are industry standards called 100mil, 75mil, 50mil, and there are more special diameters of only 0.19mm, which are mainly used for online circuit testing and functional testing. Also called ICT test and FCT test. It is also one of the most widely used probes.

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2.Interface Probes
Non-standard probe
3. MicroSeries Probes
The center distance between two test points is generally 0.25mm to 0.76mm.
4. Switch Probes
A single switch probe has two currents.
5. Coaxial Probes
For testing high-frequency signals, there are shielded loops that can test up to 10GHz and 500MHz without shielded loops.
6. Rotator Probes
The elasticity is generally not high, because its penetration is inherently strong, and it is generally used for PCBA testing processed by OSP.
7. High Current Probes
The diameter of the probe is between 2.54mm and 4.75mm. The maximum test current can reach 39amps.
8.Semiconductor Probes
The diameter is generally between 0.50mm-1.27mm. Bandwidth greater than 10GHz, 50Ω characteristic
9.Battery and Connector Contacts
Generally used to optimize contact results, good stability and long life