1. Values ranged from fractions of an ohm to 22 megohms . 2. Ultra-pure water could achieve 18 megohms or more. 3. The 2 megohm cartridge resistor is replaceable so the user can try different values. 4. The most common design inserts a 9 megohm resistor in series with the probe tip. 5. Acceptable insulator resistance values are typically 1 to 10 megohms , depending on the standards referenced. 6. Thus in the past, megohm -cm was used, sometimes abbreviated to " megohm ". 7. Thus in the past, megohm-cm was used, sometimes abbreviated to " megohm ". 8. In the case of transistor current sources, impedances of a few megohms ( at DC ) are typical. 9. In the case of transistor current sources, impedance of a few megohms ( at low frequencies ) is typical. 10. Having the grid leak resistor, even in the Megohm range, shunting signal to ground loads the received signal.