The invention discloses a teaching demonstration instrument capable of being made by oneself, which belongs to the field of teaching instrument demonstration. The teaching demonstration instrument is composed of a self-made
capacitor, a change-over switch, a test hole, an oscillator stage, a power
amplifier stage, an amplification stage, an equilibrium stage, a
voltage division stage, display stages and voice stages. The teaching demonstration instrument aims at allowing students to make objects such as instruments, inductors, capacitors resistors by themselves, and cultivating operational ability of the students. When the self-made
capacitor is inserted into the test hole and the change-over switch is in a switching-on state, namely, in a
direct current state, the display stages only flash once; when in an
alternating current state, namely, the change-over switch is in a switching-off state, the oscillator stage oscillates, high-low conversion of power
amplifier stage output occurs, the self-made
capacitor forms a charging-discharging state, the equilibrium stage is broken down through amplification by means of the amplification stage, the
voltage division stage is started, the display stages and the voice stages form light and sound display, and when oscillation frequency is accelerated, the more display states and the voice stages are started, thus the conductive performance of the object is displayed from another aspect, and the teaching demonstration instrument can be an instrument popularized in schools.