Abstract: A method and an electronic circuit for measuring very weak signals at high voltage. The electronic circuit consists of a first portion (I) constituted by at least one amplifier (2) which is DC-connected directly to a source of weak signals. This amplifier is followed by at least one current amplifier (5). A second portion of the circuit (II) then transfers the amplified current signal from high potential to the ground potential of measuring apparatus by a series of transistors (12 to 14) followed by an output amplifier (22). An optional third portion (III) may be provided to sample the signal by an analog gate (25) suitably controlled from an external frequency source. This makes it possible in spectrometry to perform fast and accurate measurements on very weak signals at high potential.

Abstract: The amplifier comprises at least two amplifier units or transistors T.sub.1 and T.sub.2 of complementary types. The base of the first transistor T.sub.1 is connected to a control current supply line. The emitter of the transistor T.sub.1 is connected on the one hand to one end of the load impedance and on the other hand to the base of the second transistor T.sub.2. The collector of the transistor T.sub.1 is connected to a voltage supply of suitable polarity. The emitter of the transistor T.sub.2 is connected to the current supply line and the collector of said transistor is connected to another end of the load impedance.