| 摘要 |
A change-over circuit for use in a tester for changing over a load and a driver to be connected to a device under test is implemented by using diode-bridge type analog switches which include a first diode-bridge type analog switch connected as collector loads for first and second transistors, a second diode-bridge type analog switch connected as collector loads for third and fourth transistors, respectively. The driver is connected to an input of the first diode-bridge type analog switch. The load circuit is connected to an input of the second diode-bridge type analog switch. The first and second diode-bridge type analog switches are so interconnected as to perform a differential operation in response to an ON/OFF control signal applied to the fourth transistor from the first transistor for thereby changing over the current and capacitive loads and the driver to be coupled to the device under test which is connected to outputs of the first and second diode-bridge type analog switches. The current and capacitive loads can both be turned on and off through differential cooperation of the first and second diode-bridge type analog switches to thereby allow the current and capacitive loads to be connected simultaneously or separately only when the driver is disabled or inhibited. Inexpensive and simplified switch circuit is thus provided.
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