Electric OU: Supplement: FG + Battery + LED + Meter = Current Flow
A function generator is a clocked, positive-negative power supply with an internal impedance of 50 ohms. You can add offsets to the FG’s output, just as if it were a battery or power supply, simply by putting another power supply in series with the FG. The total voltage is then the ALGEBRAIC SUM of the voltage from the FG and the voltage from the series battery or other fixed or even VARIABLE supply like another function generator at any given instant. The FG’s internal impedance is usually 50 ohms as standard. In case the Texan narration is too accented for speakers of proper English to understand, I will outline it here. For those who cannot read or interpret written English…. just turn the sound down and watch. If you know scopes and test equipment you will understand perfectly clearly without any words at all. If you don’t… no amount of narration will help you, I am afraid. 1) The FG is set to produce a slow sine wave of plus/minus six volts. 2) The LED and moving-coil ammeter are in series with the FG’s output. 3) The LED is shown to light and the meter indicates CURRENT whenever the FG’s sine wave output exceeds about 3 volts. 4) Then the FG’s signal OFFSET control is used to offset the FG’s signal so that it is entirely negative and the LED no longer lights and of course the meter shows no current. 5) Then… making no other changes and without harming any small animals or components… an ordinary Chinese 9 volt battery is hooked in STRICT SERIES with the …
