Voltage monitor with visible level indicator

摘要

There is provided a voltage monitor which monitors a first voltage. A means for providing a reference second voltage is provided. Also, a signal third voltage which is obtained from and is proportional to the first voltage is provided. A comparison amplifier for comparing the reference second voltage and the signal third voltage produces an output voltage which goes to a first polarity when the signal third voltage exceeds the reference second voltage and which goes to a second polarity when the signal third voltage is less than the reference second voltage. Also, there is provided at least one indicator and at least one driver amplifier which amplifies the output voltage and drives the indicator into a first state when the output voltage shows that the signal third voltage exceeds the reference second voltage, and drives the indicator into a second state when the output shows that the signal third voltage is less than the reference second voltage. The circuit is arranged so that the power supply voltage and current for all elements of the voltage monitor are taken from the first voltage to be monitored.