W8TEE TFT/ VFO DISPLAY BOARD
¿ªÔÆÌåÓýJack ? Thanks. Question:? External power on picture states 7-9 volts. I have been using 12 volts. I assume my assumption is wrong and that a voltage regulator is needed to reduce 12v to 7-9 v for the external power input? ? ? Art From: [email protected] [mailto:[email protected]] On Behalf Of Jack Purdum via Groups.Io
Sent: Friday, July 14, 2017 4:46 PM To: [email protected] Subject: Re: [BITX20] W8TEE TFT/ VFO DISPLAY BOARD ? All: ? Thought this might help some of you decipher some of the pins coming out from the board. ? ? Jack, W8TEE ? |
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Jack Purdum
The power that comes into the B40 through two 2 480uF electrolytic caps and a 0.1uF bypass cap at a little over 12V. I have that tied to the power supply feed for the PA. That 12V is then fed through a 7808 and another set of 2 480uF and 0.1uF caps. The output from that is fed at about 8V to the external power connector you mentioned. The regulator on the Mega can actually handle up to about 15V, but that really stresses it, so I backed off that to 8V. Jack, W8TEE From: Art Olson <olson339@...> To: [email protected] Sent: Friday, July 14, 2017 6:19 PM Subject: Re: [BITX20] W8TEE TFT/ VFO DISPLAY BOARD Jack ? Thanks. Question:? External power on picture states 7-9 volts. I have been using 12 volts. I assume my assumption is wrong and that a voltage regulator is needed to reduce 12v to 7-9 v for the external power input? ? ? Art From: [email protected] [mailto:[email protected]] On Behalf Of Jack Purdum via Groups.Io Sent: Friday, July 14, 2017 4:46 PM To: [email protected] Subject: Re: [BITX20] W8TEE TFT/ VFO DISPLAY BOARD ? All: ? Thought this might help some of you decipher some of the pins coming out from the board. ? ? Jack, W8TEE ?
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