Mains Remote Transmitter
Published in issue 312, July 2002
This circuit can be used to superimpose a 143-kHz carrier on the mains voltage, which allows various applications to be realised. One example is the ‘Mains Remote Switch’. Besides the power supply, the circuit consists of only a sine-wave oscillator, a buffer stage and an output transformer for isolation from the mains network.The oscillator, which is built around IC1a, is a standard Wienbridge design whose frequency is determined by R1, C1, R2 and C2. The combination of R3, R4 and the amplitude stabilisation circuitry built around T1 provides a gain of 3.
Resistors:
R1,R2 = 1k10 1%
R3 = 47kOhm
R4 = 22kOhm
R5,R18,R19 = 2kOhm 2
R6,R7 = 1MOhm
R8,R10 = 10kOhm
R9,R16,R17 = 220kOhm
R11 = 4kOhm 7
R12 = 1kOhm
R13,R14,R15 = 10Ohm
P1 = 5kOhm preset
Capacitors:
C1,C2 = 1nF 1%
C3,C7 = 100pF
C4 = 1nF
C5,C6 = 470pF
C8 = 4nF7
C9 = 330nF
C10 = 1µ F 275VAC, Class X2, lead pitch 27.5 mm
C11 = 100nF
C12,C14 = 10µ F 63V radial
C13 = 100nF ceramic, lead pitch 5 mm
C15 = 470µ F 25V radial
Semiconductors:
D1,D2,D3 = 1N4148
D4,D5 = zener diode 4V7 1.3W
T1,T2,T3 = BF245A
T4 = BD139
T5 = BD140
IC1 = AD827JN Analog Devices (Farnell)
IC2 = 7812
Miscellaneous:
K1 = 4-way pinheader
K2 = 2-way PCB terminal block, lead pitch 7.5mm
B1 = B80C1500 (rectangular case) (80V piv, 1.5A)
F1 = fuse, 32mAT (slow), with PCB mount holder and cap
Tr1 = 6:1 N30 core 16x6.3 mm EPCOS B64290L45X830 (Farnell)
Tr2 = mains transformer 15V >3VA, dims. 35x41mm, e.g., Hahn BV EI 382 1193 (15 V/4.5 VA) or Block VB 3,2/ 1/ 15 (15 V/3.2 VA, short-circuit resistant)
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Click below to download a PDF copy of this article from Elektor magazine. Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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