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Oscillators: Astable Circuits
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MICROPOWER C-MOS OSCILLATOR, DRAWS ONLY 0.5uA (6) (500na0)
If truly low power oscillators interest you, this circuit draws a mere 2 watts (500nA) from a 6v battery. It uses a very inexpensive C-MOS IC to produce a frequency of 2Hz. However, by changing the component values you can push it to 300Hz. The circuit draws much less current than traditional C-MOS oscillators using a Schmitt trigger inverter. It also produces fast leading edges. However, if you need more drive current, a C-MOS buffer should be included. Published in EDN, September 2, 1993.
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| PRECISION ULTRA LOWER POWER OSCILLATOR (49) (10secosc)
This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery. It is highly stable under varying temperature and supply voltages. |
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| VERY LOW POWER ASTABLE MULTIVIBRATOR (53) (astable)
This classic circuit draws only 200 nanoamps from a 1.5v supply. |
| CHEAP LOW POWER 3V 2Hz OSCILLATOR (62) (2hzosc)
This is yet another method to generate low frequency output pulses. The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs. It could easily be modified to produce pulse frequencies from about one cycle per minute to a maximum of about 10KHz. It draws only about 1uA from a 3v battery. This circuit should not be used if frequency stability is important, since it will change as a function of supply voltage. |
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CMOS SCHMITT TRIGGER IC MAKES VCO (124) (4584vco)
By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1. A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal.
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