Circuit with minimum number of components provides stable outputs of 2 to 8 volts at frequencies of .001 to 100 kHz. Oscillator exhibits low power consumption, portability, simplicity, and drive capability, it has application as loudspeaker tester and audible alarm, as well as in laboratory and test generators

Lipoma, P. C.

English

NASA Technical Reports Server

April 1971	 Brief 71-10089 
NASA TECH BRIEF 
Manned Spaccrajt Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a aubscription basis from the National Technical Information 
Service, Springfield,' Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Wein Bridge Oscillator Circuit 
An oscillator circuit designed with a minimum 
number of components provides stable outputs of 
2 to 8 volts at frequencies of .001 to 100 kHz. 
Prior techniques required at least three basic stages, 
R2	 C2 
and do not exhibit the low power consumption, 
portability, simplicity, and drive capability achieved 
with this design. The oscillator, due to its low cost 
and high performance, has application as a loud-
speaker tester and an audible alarm (when connected 
to a loudspeaker), as well as in laboratory and field 
test generators, and in timing generators. 
The design provides a stable, low distortion 
Wein bridge oscillator-driver capable of driving load 
impedances of less than 10 ohms as well as 
large capacitive loads. In the circuit (see fig.), RI
was selected to equal the typical input impedance 
of the amplifier, and R2 to equal RI shunted by 
the amplifier input impedance. Cl and C2 are equal 
and provide the reactive components in, a positive 
feedback configuration. C3 compensates the amplifier, 
while Li provides the necessary automatic gain con-
trol function. R3 provides the required negative feed-
back and also the limited control of the output 
amplitude. A slight amount of crossover distortion 
is exhibited at the higher frequencies due to the 
amplifier output stage. The frequency of oscillation 
	
is expressed by the formula:	
1 
27r RIC1	 =	 2ir R2C2 
The circuit has been implemented and tested, and it 
meets the above criteria, exhibiting very good power 
supply immunity and high lamp-life expectancy. 
Notes: 
1. This circuit can be implemented inexpensively, 
and performance is comparable to circuits several 
times as expensive. A complete test generator can 
be packaged into small volume and will consume 
only about 100 mW of power plus that required 
to drive the load. 
2. Two critical, elements in the circuit are: the 
amplifier (Zi, MC1454) which makes this unique 
circuit and associated performance possible; and the 
1 amp (Li) element which must be a very low 
voltage, low current device for proper circuit 
operation. 
3. Requests for further information may be directed 
to:
Technology Utilization Officer 
Manned Spacecraft Center, Code JM7 
Houston, Texas 77058 
Reference: B71-10089
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19710000088 2020-03-17T02:22:18+00:00Z
Patent status: 
No patent action is contemplated by NASA. 
Source: Phillip C. Lipoma of

Lockheed Electronics Co.

under contract to

Manned Spacecraft Center

(MSC-13686) 
Brief 71-10089
Category 01


Wein bridge oscillator circuit

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