IT IS GOOD to note that at least in Montgomery County, the latest 120-day pause in condominium conversions has produced some thoughtful long-range proposals from County Executive Charles W. Gilchrist. They are not all that complicated, either. In addition to some emergency protections just enacted this week, and instead of yet another moratorium, Mr. Gilchrist suggests a 4 percent condominium-conversion tax -- with the resulting revenue being used to ease "desperate hardships" imposed on tenants. It would be a one-time transfer tax, to be paid by the initial seller of a condominium unit.

Part of the money raised -- an estimated $4.8 million next year -- would be spent to expand the county's rent subsidy program. Units selling for less than $35,000 would be exempt from the tax. Mr. Gilchrist also suggests exemptions for certain projects as a way of encouraging developers to sell some units to low-to-moderate-income families at discounted prices, or to tenant cooperatives.

The county executive also proposes a county fund for emergency payments to displaced and handicapped tenants, and provisions to encourage below-market loans for rentals. And, in what is sure to generate political flak from tenants who think it's up to property owners to absorb all the impacts of inflation, Mr. Gilchrist favors the expiration of rent controls as scheduled by the end of 1980.

While it is true that a new tax would probably just be tacked onto the selling price of a new condominium unit, Mr. Gilchrist notes that market conditions would prevent huge increases in sales prices. Still, it may be that the tax should be even higher; County Council President Neal Potter is thinking about proposing a 10 percent rate, to slow the rate of conversions.

In any event, Mr. Gilchrist has presented the council and the state legislature in Annapolis with some sensible responses to balance the help tenants seek with the rights of property owners.