Oscillators:  Astable Circuits
Last Updated on: Saturday, April 26, 2008 07:13 AM

Oscillator Circuits -- Main Page

• CHEAP LOW POWER 3V 2Hz OSCILLATOR
  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.

• CMOS SCHMITT TRIGGER IC MAKES VCO
  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.

• Low Power Oscillators This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 microamp of current.  (added 12/04)

• MICROPOWER C-MOS OSCILLATOR, DRAWS ONLY 0.5uA
  If truly low power oscillators interest you, this circuit draws a mere 2 microwatts (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.

• Oscillator Draws 2 Nanoamps
  This page shows two low frequency oscillators that draw ultra low current.

• PRECISION ULTRA LOWER POWER OSCILLATOR
  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.

• VERY LOW POWER ASTABLE MULTIVIBRATOR
  This classic circuit draws only 200 nanoamps from a 1.5v supply.

• Ultra Low Power Astable Multivibrator
  Taking advantage of some new voltage comparators, this circuit can produce a nice square wave signal while drawing only 1.6 microamps.  With the inclusion of a diode, the circuit can also produce short pulses instead of a square wave signal.  (added 12/04)