Hi.
Inspecting an old scanner I have (Bearcat 700A) , noticed its chassis is not connected to battery minus power jack. It is a 12VDC supplied unit meant for mobile use, or with a 120VAC-to-12VDC supply.
Its antenna jack is connected to chassis. There is several small capacitors between chassis and negative power jack. There is thumbscrews meant to hold it to a holder that is supposed to be grounded to the car, joining its chassis to car body.
An internal 7805 regulator puts almost all circuitry to work on 5VDC
Why is it built that way ? What is convenient about having it in such configuration ?
Inspecting an old scanner I have (Bearcat 700A) , noticed its chassis is not connected to battery minus power jack. It is a 12VDC supplied unit meant for mobile use, or with a 120VAC-to-12VDC supply.
Its antenna jack is connected to chassis. There is several small capacitors between chassis and negative power jack. There is thumbscrews meant to hold it to a holder that is supposed to be grounded to the car, joining its chassis to car body.
An internal 7805 regulator puts almost all circuitry to work on 5VDC
Why is it built that way ? What is convenient about having it in such configuration ?