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DC Voltage Switch

IP.com Disclosure Number: IPCOM000087728D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Debord, P: AUTHOR

Abstract

Shown in the drawing is a DC voltage switch which presents an apparent AC impedance that is lower than 0.5 ohm.

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DC Voltage Switch

Shown in the drawing is a DC voltage switch which presents an apparent AC impedance that is lower than 0.5 ohm.

The switch comprises optocoupler OPT, transistor T1, transistor T2 and low voltage amplifier A. Optocoupler OPT, which comprises a light-emitting diode and a phototransistor, controls the status of the switch: when it is off, the switch is on, and conversely. Amplifier A comprises transistors T3,T4 and T5 and resistors R1 to R7.

When optocoupler OPT is off, transistor T1 is saturated, its base being connected to potential + V through resistors R8 and R9 and its emitter being connected to the lower potential of node C through resistors R1, R2 and R3. Consequently, low voltage amplifier A is powered and controls the base of transistor T2, establishing a constant voltage between nodes B and C.

When optocoupler OPT is on, transistors T1 and T2 are off, which causes the switch to be off.

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