Direct-current power supply input anti-reverse-connection, anti-overvoltage protection and overvoltage alarm circuit

The utility model discloses a direct current power supply input anti-reverse connection, anti-overvoltage protection and overvoltage alarm circuit, which is characterized by comprising a normally open switch, a linear voltage stabilizing circuit, an alarm module, a first diode, a second diode, a field effect transistor and a triode. According to the DC power supply input anti-reverse-connection and anti-overvoltage protection circuit provided by the utility model, when the input is in reverse connection, the linear voltage stabilizing circuit does not work, and the field effect transistor cannot be turned on, so that an anti-reverse-connection effect can be achieved. When the input voltage is overvoltage, the alarm module gives an alarm, and the triode can pull down the output voltage of the linear voltage stabilizing circuit to the ground, so that the field effect transistor does not work, the input overvoltage voltage transmission loop is cut off, and the overvoltage protection effect is achieved. 本实用新型公开了一