Thanks, Steve! I'm surprised it works at all too, and I'm curious how it would sound with a good transistor. The hospital recommendation was odd to me too, maybe it's because of the earphone-only operation.
I'm surprised they didn't just use a plastic tuning capacitor of the type found in most pocket sized transistor radios, that would have allowed them to use a smaller knob.
You probably had to live next door to the transmitter to pick anything up! I can't imagine this impressing anyone with its performance. Probably why it still has the box. Must have been a great talking point though... being powered by light. Clever stuff over 60 years ago. Thank you for showing us.
Thanks Colin! I also doubt this radio was a good performer back when it was new, but it at least had the novelty of being powered by the sun. I have noticed that the radios which are mostly likely to still have the box are ones that were mediocre performers, but were too nice to just throw out, as well as radios with a nice gift box... this radio falls into both categories!
Crystal radio with a transistor but how would it even work because the crystal earphone wood block the DC voltage from the solar cell from reaching the transistor
@@shango066 Hi Shango066 ... I have not seen a schematic for this set yet but most likely there is a load-resistor in series with the collector circuit of the output transistor and the crystal earphone is in parallel with that resistor.
@@shango066 ... Now that I have watched the video I see the schematic at 06:06 and also I see the earphone and it looks like a magnetic type... looks kinda like a hearing-aid earphone.
@@shango066 It uses a high-impedance (~1400 ohm) magnetic earphone, so they were able to avoid using a load resistor like some crystal radios that have a crystal earphone.
Most likely a germanian transistor which would have a lower forward voltage than a silicon. That would allow it to work with the low voltage of that silenium solar cell. Cool little radio. Now, go find a Sinclair Micromatic AM radio. Thanks for the video.
It uses a germanium transistor, as did all consumer transistor radios in 1957. Silicon transistors didn't start catching on until the 1960's. You are right that the forward voltage of germanium transistors is lower, and that's really important in this case. I have the Clairtone version of the Sinclair Micromatic around here somewhere.
I have a few Acopian supplies and power modules.. I didn't know they put this radio out! I wouldn't fool with that - such a cool artifact - but you could consider building a similar circuit with some new parts. It would be interesting to see how it would perform. Obviously not well, but maybe a bit louder?
Neat radio! Check your email in a few days, will have info on topic for you. Just a FYI, in regards to the low voltage output, Selenium dies over time...this is a big issue with film cameras that have Selenium meters, the only thing you can do to help prolong its life is keep it in a dark container when not in use, I keep my cameras in a bag in a box in a black tote. ~Jack, VEG
Thanks, Jack! That's good to know about the output of selenium cells decreasing over time. I keep it in the original box, so it's been protected from light for most of it's life. I'll keep an eye out for that email!
that earpiece looks like one from a crystal radio i used to own, that i made in cub scouts. i don't know why it would use a solar cell. crystal radios did not use power.
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Matt - thanks for sharing this. A very cool historical Solar Radio! A great find in excellent condition w/ the documentation, etc. All the best. Don
Thanks Don! This was a cool find for sure, there can't be too many of them out there with the box and all the goodies.
Thanks for sharing this with us. A novelty, for sure.
Thanks, Colin! Yeah, it's definitely an interesting novelty.
it's amazing that the transistor works at all. It's funny they recommend it be used in hospitals! Thanks for the video!
Thanks, Steve! I'm surprised it works at all too, and I'm curious how it would sound with a good transistor. The hospital recommendation was odd to me too, maybe it's because of the earphone-only operation.
They recommended the use in hospitals for curative reasons.
Interesting.
I’ve seen a couple of Hoffman radios, but never this.
Very interesting,
- now, tons of Emergency Radios have solar power.
📻🙂
It seems to be a lot less common than the later Hoffman solar radios, I've only seen a few of these.
I'd love one of those but I fear my neighbours would complain about the loud music.
LOL it's so loud I couldn't bear to try it out!
No volume control? Might as well just use a crystal radio... LOL.
Wonder why they used that crazy knob for tuning, instead of a thumbwheel.
I'm surprised they didn't just use a plastic tuning capacitor of the type found in most pocket sized transistor radios, that would have allowed them to use a smaller knob.
You probably had to live next door to the transmitter to pick anything up! I can't imagine this impressing anyone with its performance. Probably why it still has the box. Must have been a great talking point though... being powered by light. Clever stuff over 60 years ago.
Thank you for showing us.
Thanks Colin! I also doubt this radio was a good performer back when it was new, but it at least had the novelty of being powered by the sun. I have noticed that the radios which are mostly likely to still have the box are ones that were mediocre performers, but were too nice to just throw out, as well as radios with a nice gift box... this radio falls into both categories!
Crystal radio with a transistor but how would it even work because the crystal earphone wood block the DC voltage from the solar cell from reaching the transistor
@@shango066 Hi Shango066 ... I have not seen a schematic for this set yet but most likely there is a load-resistor in series with the collector circuit of the output transistor and the crystal earphone is in parallel with that resistor.
@@shango066 ... Now that I have watched the video I see the schematic at 06:06 and also I see the earphone and it looks like a magnetic type... looks kinda like a hearing-aid earphone.
@@shango066 It uses a high-impedance (~1400 ohm) magnetic earphone, so they were able to avoid using a load resistor like some crystal radios that have a crystal earphone.
Most likely a germanian transistor which would have a lower forward voltage than a silicon. That would allow it to work with the low voltage of that silenium solar cell.
Cool little radio. Now, go find a Sinclair Micromatic AM radio.
Thanks for the video.
It uses a germanium transistor, as did all consumer transistor radios in 1957. Silicon transistors didn't start catching on until the 1960's. You are right that the forward voltage of germanium transistors is lower, and that's really important in this case. I have the Clairtone version of the Sinclair Micromatic around here somewhere.
I have a few Acopian supplies and power modules.. I didn't know they put this radio out! I wouldn't fool with that - such a cool artifact - but you could consider building a similar circuit with some new parts. It would be interesting to see how it would perform. Obviously not well, but maybe a bit louder?
I plan to leave it be, since it's a nice historical piece. I would rather it worked though.
Neat radio! Check your email in a few days, will have info on topic for you. Just a FYI, in regards to the low voltage output, Selenium dies over time...this is a big issue with film cameras that have Selenium meters, the only thing you can do to help prolong its life is keep it in a dark container when not in use, I keep my cameras in a bag in a box in a black tote. ~Jack, VEG
Thanks, Jack! That's good to know about the output of selenium cells decreasing over time. I keep it in the original box, so it's been protected from light for most of it's life.
I'll keep an eye out for that email!
cool !
Thanks
that earpiece looks like one from a crystal radio i used to own, that i made in cub scouts. i don't know why it would
use a solar cell. crystal radios did not use power.
Use your PC mic input to capture the audio.
It's too low even for that, it's barely audible right in my ear. If I do end up replacing the transistor, I'll record the audio.
Shine one of Styropro's lasers into that solar panel, you'll get some output...
That'd probably get it to play, for a moment at least
The sun is a deadly laser