I need a circuit for a constant current source using a 1.5v battery and a DC poswer supply.
2007-01-29 11:56:26 · 2 answers · asked by Sparky 2 in Science & Mathematics ➔ Engineering
First off, a battery is a DC power supply. As constant current, it is probably not good since the voltage of the battery will decrease over time. You may want to use a battery as a backup and use a rectifier as your main source. You will probably want to get a rechargable battery also.
You will probably use a switch to cut in the battery when power interupts. You should be able to do this with solid state as well.
2007-01-29 12:07:30 · answer #1 · answered by Poncho Rio 4 · 0⤊ 0⤋
Use the battery to connect to the base of a transistor that has a resistor between the Emitter and Ground. The current through the collector on a relatively high gain > 100 transistor will be roughly constant and equal to (1.5-.6)/Re where Re is the resistor connected to the emitter.
2007-01-29 15:19:16 · answer #2 · answered by rscanner 6 · 0⤊ 0⤋