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Some of the transistors and the lamp-LDR combination used in this sine

wave generator project are obsolete. However, they can be easily

replaced by more modern items:

N-channel JFET E102: replacement types are BF244B, 2N4302,2N4303, 2N5458, 2N5459

NPN transistor 2N3708: use BC548 or BC549

PNP transistor 2N4059: use BC558

NSL PSL 1033-1 (lamp-LDR combination): use an LDR with a darkresistance of 10 Mega-ohms and a light resistance of approximately

100 ohms, the lamp is a 9 or 10V grain-of-wheat type drawing 15mA.

There are a few nice features in this design:

1. The range of 10 Hz100 kHz is split in 8 rather than the more usual4 sections. This allows a more easy and accurate setting of the

output frequency.

2. For stabilization of the output amplitude, a lamp-LDR combination isused rather than a miniature glass-type NTC resistor (which may bequite difficult to obtain and may also be expensive)

3. The output of the generator should be set to 2 V eff, using trim pot

TP1, e.g. at a frequency of 50 Hz.

4. Although the sinewave distortion is not very low (< 0.5% throughoutthe entire range), distortion performance is good for such a simpledesign and smaller in the middle of the range than at the frequency

extremes.

Digitized by A.van Waarde, januari 2010