  Using a relaxation oscillator circuit, breakdown ($V_{\mathrm{BD}}$) and
quench ($V_{\mathrm{Q}}$) voltages of a DC discharge microplasma between two
needle probes are measured. High resolution modified Paschen curves are
obtained for argon microplasmas including a quench voltage curve representing
the voltage at which the plasma turns off. It is shown that, for a point to
point microgap (e.g. the microgap between two needle probes) which describes
many realistic microdevices, neither Paschen's law applies nor field emission
is noticeable. Although normally $V_{\mathrm{BD}}>V_{\mathrm{Q}}$, it is
observed that depending on environmental parameters of argon, such as pressure
and the driving circuitry, plasma can exist in a different state with equal
$V_{\mathrm{BD}}$ and $V_{\mathrm{Q}}$. Using emission line spectroscopy, it is
shown that $V_{\mathrm{BD}}$ and $V_{\mathrm{Q}}$ are equal if the atomic
excitation by the electric field dipole moment dominantly leads to one of the
argon's metastable states ($4P_{5}$ in our study).
