Components List Of Single Conversion 6 Transistor FM Receiver
FM Tuner Section
Resistors .05 Watt Carbon Film.
R1 150K. R2 27K. R3 270R. R4 270R. R5 100K. R6 2K2. R7 100K. R8 2K2. R9 4K7. R10 470R. R11 150K. R12 27K. R13 270R. R14 270R. R15 27K. R16 150K. R17 270R. R18 270R. R19 100K. R20 1K8. R22 4K7. R23 47K.
Capacitors Ceramic Disc
C1 1NF. C2 1NF. C3 1NF. C4 100NF. C5 10PF. C6 22PF. C7 10NF. C8 5PF. C9 100NF. C11 100NF. C13 10NF. C14 10NF. C15 100NF C17 10NF. C18 10NF. C19 100NF. C21 100PF. C22 100NF. C24 470PF. C25 100PF. C26 100NF.
C10 C12 C14 C20 C23 100uf 16 minimum working volts. C27 1000uf 16 minimum working volts.
Variable and trimmer capacitors
TC1 TC2 TC3 TC 4 15-30PF Trimmer. VC1 15-30PF Variable air spaced capacitor available from the following suppliers Jackson Brothers - Variable Capacitors and Drives or another recommended supplier Ocean State Electronics and also Antique Electronic Supply
TR1 TR2 TR4 TR5 40673 Dual gate FET. TR3 BF244 Single channel FET. TR6 2N3819 Single channel FET. D1 D2 0A91 Germanium Diode. All available from http://www.cricklewoodelectronics.com
IFT1 IFT2 IFT3 IFT4 You will need 8 of the Following IF transformers, Toko TKAC-S34342BM available from BEC Distribution Limited . As Field effect transistors have high input impedance characteristics similar to valves, I am afraid single units can not be used. L1 L2 L3 L4 7 turns of 16 SWG enamelled or tinned copper wire of about 10mm diameter air spaced. Alternatively 2.5 millimetre UK ring mains cable, with its conductors stripped down gives very good results.
9 Volt power supply
6 AA size Duracell type batteries if used as a mono tuner alone or 6 D size batteries when used with LM386 audio amplifier or stereo decoder. A stabilized 9 Volt mains power supply unit of about 1.5 amps minimum output is recommended for continues home use or when using the stereo decoder. NB The use of switch mode mains adaptors is not recommended. Do not also try to use the type power supply that is used for model railways or toy racing sets as the output is not smooth DC and could damage the transistors.
LM386 Amplifier for mono portable
R1 47K. R2 8R2. VR1 10K.
C1 100NF Disc ceramic. C2 10NF Disc ceramic. C3 22uf 16V electrolytic. C4 4.7uf 16V electrolytic. C5 100NF Disc ceramic. C6 100uf 16V electrolytic. C7 1000uf 16V electrolytic.
LM386 IC available from http://www.cricklewoodelectronics.com
S1 Single pole toggle switch or can be combined with VR1 volume control
Plain Veroboard. Available from the following link Maplin Electronics and the board recommended at the time of writing this page is Code JU37S. It has enough space to easily build the entire receiver without every component being crammed up as it is 300 X 100mm. All my transistor FM Receivers have been built with this particular circuit board. NB Avoid the use of stripboard as there is a very high risk of stray capacitance leading to instability, particularly in the VHF Circuits. Experienced constructors can also try printed circuit board preferably double sided in the VHF circuits as this makes an excellent ground plain. Tinned copper wire for interconnections on circuit boards. Stranded wire, recommended for power connections. Case. Metal case preferable when used with the stereo decoder. NB Because VC1 tuning capacitor is at positive potential, do not allow the spindle to come in contact with the case or you will short circuit the power supply to the local oscillator.
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