Anyone ever powered a circuit with a CB radio supply before? - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: September 26, 2025, 08:17:15 pm
content: Has anyone ever used a power supply for a CB radio before? I was looking at thisPR-7 Supply, and I thought something like this could be used in a pinch to power circuits (when properly designed). But when I read the Owner's Manual, I was confused by something. For the PR7, it states an ICS amperage rating of 7 amps and a Continuous Duty Amperage of 5 amps. Furthermore, the manual specifically says that the max current draw should not exceed the continuous duty output of the supply. Given all that, what is this ICS rating for, and how does one "design" around it? Seems to me like it's the max current that can come out, but only for a limited time given their 10-minute period example.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 26, 2025, 08:30:21 pm
content: used many cb psu's and even hacked a few in the 20 or more ampsmost are based on 723 designs, some where op amps basedand yes the psu is 5 amp continuous and 7 amp surge, for that it depends on how the current limiter is built, you may find schematics on the web, normally they are fixed valuesthis psu is passively cooled, meaning no fans it may dissipate a bitand you'll pay a lot for theses psu for nothing ... 80$ usd and more ... you can find higher power psu for less

author: TimFox
author_rank: Super Contributor
timestamp: September 26, 2025, 09:04:14 pm
content: All other things being equal, a linear power supply using a 723 and pass transistors will be heavier, and run hotter, but with far less RF noise problems, than a switching power supply.Reducing the noise to an acceptable level is practicable, but requires extra engineering effort over that required to meet standard regulatory requirements.

author: Stray Electron
author_rank: Super Contributor
timestamp: September 26, 2025, 09:09:46 pm
content: X2. I don't think that Triplite makes power supplies and it looks like that is a re-badged Astron PSU. Hams loved them but to me there's nothing special about them. I've run hundreds of car radios, ham radio and CBs off of just about every kind of PS known to man and there's no special requirements. But I would avoid any modern switcher PS, especially ones made in Asia, or you'll get so much RFI that you won't be able to use the radio. If it were me I'd just go on Ebay and pick up a used good high quality HP, Lambda or other good American made LINEAR power supply or even a linear Astron PSU. They're heavier than the junk made switchers so people don't like to ship them so you can buy GOOD quality PS for next to nothing on Ebay. Especially if you're willing to drive and pick them up in person. For your application you don't need a PSU with an adjustable output or that has meters and you certainly don't need the gimmicky digital meters that come on most of today's Eye-Catching made in Asia disposable junk PSUs.Probably my cheapest PSs was a center tapped 24 volt transformer with two diodes configured in a full wave bridge and a couple of nondescript capacitors hung across the output and the whole thing stuffed into the card board box that the the x-former came in and held together with safety wire. I used it to power an AM 8-track car radio that someone had given me when I was a poor GI and living in a barracks but it worked very well! Regulation? We don need no stecken regulation!

author: Stray Electron
author_rank: Super Contributor
timestamp: September 26, 2025, 09:14:28 pm
content: PS I have no idea what ICS means but it sounds like something that they made up so that they canclaimthe PS can handle more power than it actually can. Buy HP or Lambda or something similar. If it says that it can handle seven amps then itwillbe able to handle seven amps!

author: TimFox
author_rank: Super Contributor
timestamp: September 26, 2025, 09:16:00 pm
content: If you don't need regulation, the "brute-force" supply with transformer, rectifier, and huge capacitors works nicely.Kepco used to source a line of such supplies using ferroresonant transformers for improved "line regulation" against mains voltage variation; I believe they were made by TDK.Before my retirement, we built large arrays of x-ray detectors and powered them from heavy Lambda linear power supplies.Since we already had tons of lead on the system, the extra weight didn't matter.

author: TimFox
author_rank: Super Contributor
timestamp: September 26, 2025, 09:17:20 pm
content: Quote from: Stray Electron on September 26, 2025, 09:14:28 pmTransmitting vacuum tubes used to have two power ratings: "CCS" for continuous commercial service (e.g., FM broadcast) and "ICAS" for intermittent commercial and amateur service.

author: John Coloccia
author_rank: Super Contributor
timestamp: September 29, 2025, 01:52:57 am
content: I'm surprised anyone is still making these. I have one that's decades old, from RadioShack. Simply designed to approximate what a car alternator puts out. It's hard to see why this is still relevant today.

author: Stray Electron
author_rank: Super Contributor
timestamp: September 29, 2025, 03:05:00 am
content: Quote from: John Coloccia on September 29, 2025, 01:52:57 amBecause people still use 12 VDC equipment! My ham buddies hate switcher power supplies and always have me on the look out for big high current linear 12 volt power supplies. I wish that I had saved some pictures of some of thebrutesthat I've found for them.

author: abeyer
author_rank: Frequent Contributor
timestamp: September 29, 2025, 03:20:14 am
content: Quote from: John Coloccia on September 29, 2025, 01:52:57 amI don't know of a cheaper source of reasonably powerful linear supplies anymore, and even brand new amateur radio equipment still assumes 13.8V standard.