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| What was your first circuit? Do you still remember it? |
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| TimFox:
Mine was a code-practice oscillator that I built in Cub Scouts, ca. 1960, similar to the one in the QST article linked below. It used a CK722 PNP germanium transistor from Raytheon. That, and the GE 2N107 NPN transistor, were heavily advertised to young people at that time. IIRC, they were both about $2.50 each back then. https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1959/07/page30/index.html |
| brucehoult:
--- Quote from: themadhippy on November 26, 2022, 02:06:41 pm --- --- Quote ---How on earth can you have a DPDT switch with only 4 terminals? --- End quote --- Take a look at your diagram,theirs only 4 external connections needed ,and thats what you buy off the shelf from your electrical supplier,they go under the name of intermediate switch and do exactly what you described above,sit between 2 way switches to add a 3rd,4th -999th switching position.They really should rename them universal switch as they can be used for the most common switching arrangements found on lighting circuits. --- End quote --- Well great if this is common enough they make specialised switches for this. I've only seen general-purpose DPDT switches, but I'm a hobbyist doing low voltage stuff not a sparky, and 6 terminal DPDT switches are possibly the MOST common kind. https://sparks.gogo.co.nz/catalog/Buttons-Switches-Relays-261/Miscellaneous-100/DPDT--AB--Small-Panel-Mount-Toggle-Switch-6mm-Thread-1015.html |
| TimFox:
A DPDT switch hard-wired to only four terminals is often called a "reversing switch", or in US domestic lighting a "four-way switch", which is connected between two or more "three-way switches" (SPDT) to control lighting along a corridor, etc. |
| themadhippy:
--- Quote ---.6 terminal DPDT switches are possibly the MOST common kind. --- End quote --- in the electronics world agreed,however what surprised me is --- Quote ---but I noticed the switches being installed were actually DPDT. --- End quote --- as ive yet to see a dpdt switch in a standard light switch format |
| mawyatt:
--- Quote from: TimFox on November 26, 2022, 06:42:34 pm ---Mine was a code-practice oscillator that I built in Cub Scouts, ca. 1960, similar to the one in the QST article linked below. It used a CK722 PNP germanium transistor from Raytheon. That, and the GE 2N107 NPN transistor, were heavily advertised to young people at that time. IIRC, they were both about $2.50 each back then. https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1959/07/page30/index.html --- End quote --- Remember those CK722s, one of the early plastic cased transistors. You could shine a light on them and they responded!! First project here was a telegraph made from old scavenged lantern batteries, scrap phone wire, tin can top, scrap nails and scrap wood 2 by 4s. Tin top was cut for telegraph "key" with nail contact, and the "T" shaped "sounder" and wire wound around 2 nails as electromagnet. Was 6~7 then and parents thought I was nuts, they were probably right :o Fond memories from back then! Best |
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