One or more of the following: Tuning quantum dots to the few electron regime, measuring quantum dot threshold voltages, charge noise, noise spectroscopy, valley splitting; qubit readout, qubit spin state readout, measuring fidelity, qubit spin resonance, coherence time, relaxation, T1, T2, Rabi, Ramsey, CPMG, Hahn Echo, Pauli Spin Blockade, spin orbit, quantum gates, or Bell State, GHZ, tomography, or algorithms. Electrical measurements of spin qubits, singlet-triplet qubits, exchange only qubits, semiconductor qubits, and/or quantum well heterostructures, preferably in silicon, Si/SiGe or Ge/SiGe.