136:
155:, the potential difference between its inputs tends to zero when a feedback network is implemented. This means that the output supplies the inverting input (via the feedback network) with enough voltage to reduce the potential difference between the inputs to microvolts. More precisely, it can be shown that the output voltage of the amplifier in the figure is approximately equal to
215:. Thus, as far as the amplifier is working in its linear region (output not saturated, frequencies inside the range of the opamp), the voltage at the inverting input terminal remains constant with respect to the real ground, and independent from the loads to which the output may be connected. This property is characterized a "virtual ground".
28:) is a node of a circuit that is maintained at a steady reference potential, without being connected directly to the reference potential. In some cases the reference potential is considered to be that of the surface of the earth, and the reference node is called "ground" or "earth" as a consequence.
130:
58:, using two resistors, can be used to create a virtual ground node. If two voltage sources are connected in series with two resistors, it can be shown that the midpoint becomes a virtual ground if
31:
The virtual ground concept aids circuit analysis in operational amplifiers and other circuits and provides useful practical circuit effects that would be difficult to achieve in other ways.
213:
250:
234:). Usually, the power supply terminals serve as steady grounds; when the internal points of compound power sources are accessible, they can also serve as real grounds.
64:
42:
may have any value of current or voltage but physical implementations of a virtual ground will have limitations in terms of current handling ability and a non-zero
290:
237:
If there are no accessible source internal points, external circuit points with steady voltage relative to the source terminals can serve as artificial
333:
344:
254:
328:
158:
294:
365:
360:
314:
226:
is a differential quantity, which appears between two points. In order to deal only with a voltage (an
339:
125:{\displaystyle {\frac {V_{\text{out}}}{V_{\text{in}}}}=-{\frac {R_{\text{f}}}{R_{\text{in}}}}}
148:
143:
An active virtual ground circuit is sometimes called a rail splitter. Such a circuit uses an
260:
231:
227:
43:
241:. Such a point has to have steady potential, which does not vary when a load is attached.
8:
347:
shows the application of the virtual ground concept in an inverting amplifier (Archived)
336:
Application note on creating an artificial virtual ground as a reference voltage.
55:
39:
230:) of a single point, the second point has to be connected to a reference point (
152:
35:
354:
278:
329:
Create a
Virtual Ground with the LT1118-2.5 Sink/Source Voltage Regulator
17:
223:
135:
144:
147:
or some other circuit element that has gain. Since an
334:
Rail
Splitter, from Abraham Lincoln to Virtual Ground
161:
67:
207:
124:
352:
208:{\displaystyle -{\frac {R_{f}}{R_{in}}}V_{in}}
257:show some typical virtual ground applications
315:Designing Single Supply, Low-Power Systems
134:
46:which may have practical side effects.
353:
340:Creating a Virtual Power Supply Ground
13:
14:
377:
322:
218:
49:
308:
283:
272:
1:
266:
255:Current-to-voltage converter
251:Voltage-to-current converter
7:
261:Miller theorem applications
244:
10:
382:
139:Op-amp inverting amplifier
345:Inverting configuration
291:"Single Supply Op Amps"
279:Virtual Ground Circuits
209:
140:
126:
210:
149:operational amplifier
138:
127:
366:Electricity concepts
228:electrical potential
159:
65:
361:Electrical circuits
205:
141:
122:
190:
120:
117:
107:
90:
87:
77:
373:
317:
312:
306:
305:
303:
302:
293:. Archived from
287:
281:
276:
214:
212:
211:
206:
204:
203:
191:
189:
188:
176:
175:
166:
131:
129:
128:
123:
121:
119:
118:
115:
109:
108:
105:
99:
91:
89:
88:
85:
79:
78:
75:
69:
381:
380:
376:
375:
374:
372:
371:
370:
351:
350:
325:
320:
313:
309:
300:
298:
289:
288:
284:
277:
273:
269:
247:
239:virtual grounds
221:
196:
192:
181:
177:
171:
167:
165:
160:
157:
156:
114:
110:
104:
100:
98:
84:
80:
74:
70:
68:
66:
63:
62:
56:voltage divider
52:
22:virtual ground
12:
11:
5:
379:
369:
368:
363:
349:
348:
342:
337:
331:
324:
323:External links
321:
319:
318:
307:
282:
270:
268:
265:
264:
263:
258:
246:
243:
220:
217:
202:
199:
195:
187:
184:
180:
174:
170:
164:
153:open-loop gain
151:has very high
133:
132:
113:
103:
97:
94:
83:
73:
51:
48:
36:circuit theory
9:
6:
4:
3:
2:
378:
367:
364:
362:
359:
358:
356:
346:
343:
341:
338:
335:
332:
330:
327:
326:
316:
311:
297:on 2020-07-25
296:
292:
286:
280:
275:
271:
262:
259:
256:
252:
249:
248:
242:
240:
235:
233:
229:
225:
216:
200:
197:
193:
185:
182:
178:
172:
168:
162:
154:
150:
146:
137:
111:
101:
95:
92:
81:
71:
61:
60:
59:
57:
47:
45:
41:
37:
32:
29:
27:
26:virtual earth
23:
19:
310:
299:. Retrieved
295:the original
285:
274:
238:
236:
222:
219:Applications
142:
53:
50:Construction
33:
30:
25:
21:
15:
18:electronics
355:Categories
301:2007-02-04
267:References
163:−
96:−
44:impedance
245:See also
224:Voltage
232:ground
145:op-amp
253:and
40:node
38:, a
24:(or
20:, a
76:out
34:In
16:In
357::
116:in
86:in
54:A
304:.
201:n
198:i
194:V
186:n
183:i
179:R
173:f
169:R
112:R
106:f
102:R
93:=
82:V
72:V
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
